sqlparser_common.rs

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#![warn(clippy::all)]
//! Test SQL syntax, which all sqlparser dialects must parse in the same way.
//!
//! Note that it does not mean all SQL here is valid in all the dialects, only
//! that 1) it's either standard or widely supported and 2) it can be parsed by
//! sqlparser regardless of the chosen dialect (i.e. it doesn't conflict with
//! dialect-specific parsing rules).

#[macro_use]
mod test_utils;

use matches::assert_matches;
use sqlparser::ast::SelectItem::UnnamedExpr;
use sqlparser::ast::*;
use sqlparser::dialect::{
    AnsiDialect, BigQueryDialect, ClickHouseDialect, GenericDialect, HiveDialect, MsSqlDialect,
    PostgreSqlDialect, SQLiteDialect, SnowflakeDialect,
};
use sqlparser::keywords::ALL_KEYWORDS;
use sqlparser::parser::{Parser, ParserError};

use test_utils::{
    all_dialects, expr_from_projection, join, number, only, table, table_alias, TestedDialects,
};

#[test]
fn parse_insert_values() {
    let row = vec![
        Expr::Value(number("1")),
        Expr::Value(number("2")),
        Expr::Value(number("3")),
    ];
    let rows1 = vec![row.clone()];
    let rows2 = vec![row.clone(), row];

    let sql = "INSERT customer VALUES (1, 2, 3)";
    check_one(sql, "customer", &[], &rows1);

    let sql = "INSERT INTO customer VALUES (1, 2, 3)";
    check_one(sql, "customer", &[], &rows1);

    let sql = "INSERT INTO customer VALUES (1, 2, 3), (1, 2, 3)";
    check_one(sql, "customer", &[], &rows2);

    let sql = "INSERT INTO public.customer VALUES (1, 2, 3)";
    check_one(sql, "public.customer", &[], &rows1);

    let sql = "INSERT INTO db.public.customer VALUES (1, 2, 3)";
    check_one(sql, "db.public.customer", &[], &rows1);

    let sql = "INSERT INTO public.customer (id, name, active) VALUES (1, 2, 3)";
    check_one(
        sql,
        "public.customer",
        &["id".to_string(), "name".to_string(), "active".to_string()],
        &rows1,
    );

    fn check_one(
        sql: &str,
        expected_table_name: &str,
        expected_columns: &[String],
        expected_rows: &[Vec<Expr>],
    ) {
        match verified_stmt(sql) {
            Statement::Insert {
                table_name,
                columns,
                source,
                ..
            } => {
                assert_eq!(table_name.to_string(), expected_table_name);
                assert_eq!(columns.len(), expected_columns.len());
                for (index, column) in columns.iter().enumerate() {
                    assert_eq!(column, &Ident::new(expected_columns[index].clone()));
                }
                match &*source.body {
                    SetExpr::Values(Values(values)) => assert_eq!(values.as_slice(), expected_rows),
                    _ => unreachable!(),
                }
            }
            _ => unreachable!(),
        }
    }

    verified_stmt("INSERT INTO customer WITH foo AS (SELECT 1) SELECT * FROM foo UNION VALUES (1)");
}

#[test]
fn parse_insert_sqlite() {
    let dialect = SQLiteDialect {};

    let check = |sql: &str, expected_action: Option<SqliteOnConflict>| match Parser::parse_sql(
        &dialect, sql,
    )
    .unwrap()
    .pop()
    .unwrap()
    {
        Statement::Insert { or, .. } => assert_eq!(or, expected_action),
        _ => panic!("{}", sql),
    };

    let sql = "INSERT INTO test_table(id) VALUES(1)";
    check(sql, None);

    let sql = "REPLACE INTO test_table(id) VALUES(1)";
    check(sql, Some(SqliteOnConflict::Replace));

    let sql = "INSERT OR REPLACE INTO test_table(id) VALUES(1)";
    check(sql, Some(SqliteOnConflict::Replace));

    let sql = "INSERT OR ROLLBACK INTO test_table(id) VALUES(1)";
    check(sql, Some(SqliteOnConflict::Rollback));

    let sql = "INSERT OR ABORT INTO test_table(id) VALUES(1)";
    check(sql, Some(SqliteOnConflict::Abort));

    let sql = "INSERT OR FAIL INTO test_table(id) VALUES(1)";
    check(sql, Some(SqliteOnConflict::Fail));

    let sql = "INSERT OR IGNORE INTO test_table(id) VALUES(1)";
    check(sql, Some(SqliteOnConflict::Ignore));
}

#[test]
fn parse_update() {
    let sql = "UPDATE t SET a = 1, b = 2, c = 3 WHERE d";
    match verified_stmt(sql) {
        Statement::Update {
            table,
            assignments,
            selection,
            ..
        } => {
            assert_eq!(table.to_string(), "t".to_string());
            assert_eq!(
                assignments,
                vec![
                    Assignment {
                        id: vec!["a".into()],
                        value: Expr::Value(number("1")),
                    },
                    Assignment {
                        id: vec!["b".into()],
                        value: Expr::Value(number("2")),
                    },
                    Assignment {
                        id: vec!["c".into()],
                        value: Expr::Value(number("3")),
                    },
                ]
            );
            assert_eq!(selection.unwrap(), Expr::Identifier("d".into()));
        }
        _ => unreachable!(),
    }

    verified_stmt("UPDATE t SET a = 1, a = 2, a = 3");

    let sql = "UPDATE t WHERE 1";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected SET, found: WHERE".to_string()),
        res.unwrap_err()
    );

    let sql = "UPDATE t SET a = 1 extrabadstuff";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: extrabadstuff".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_update_with_table_alias() {
    let sql = "UPDATE users AS u SET u.username = 'new_user' WHERE u.username = 'old_user'";
    match verified_stmt(sql) {
        Statement::Update {
            table,
            assignments,
            from: _from,
            selection,
        } => {
            assert_eq!(
                TableWithJoins {
                    relation: TableFactor::Table {
                        name: ObjectName(vec![Ident::new("users")]),
                        alias: Some(TableAlias {
                            name: Ident::new("u"),
                            columns: vec![]
                        }),
                        args: None,
                        with_hints: vec![],
                    },
                    joins: vec![]
                },
                table
            );
            assert_eq!(
                vec![Assignment {
                    id: vec![Ident::new("u"), Ident::new("username")],
                    value: Expr::Value(Value::SingleQuotedString("new_user".to_string()))
                }],
                assignments
            );
            assert_eq!(
                Some(Expr::BinaryOp {
                    left: Box::new(Expr::CompoundIdentifier(vec![
                        Ident::new("u"),
                        Ident::new("username")
                    ])),
                    op: BinaryOperator::Eq,
                    right: Box::new(Expr::Value(Value::SingleQuotedString(
                        "old_user".to_string()
                    )))
                }),
                selection
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_invalid_table_name() {
    let ast = all_dialects()
        .run_parser_method("db.public..customer", |parser| parser.parse_object_name());
    assert!(ast.is_err());
}

#[test]
fn parse_no_table_name() {
    let ast = all_dialects().run_parser_method("", |parser| parser.parse_object_name());
    assert!(ast.is_err());
}

#[test]
fn parse_delete_statement() {
    let sql = "DELETE FROM \"table\"";
    match verified_stmt(sql) {
        Statement::Delete { table_name, .. } => {
            assert_eq!(
                TableFactor::Table {
                    name: ObjectName(vec![Ident::with_quote('"', "table")]),
                    alias: None,
                    args: None,
                    with_hints: vec![]
                },
                table_name
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_where_delete_statement() {
    use self::BinaryOperator::*;

    let sql = "DELETE FROM foo WHERE name = 5";
    match verified_stmt(sql) {
        Statement::Delete {
            table_name,
            using,
            selection,
        } => {
            assert_eq!(
                TableFactor::Table {
                    name: ObjectName(vec![Ident::new("foo")]),
                    alias: None,
                    args: None,
                    with_hints: vec![]
                },
                table_name,
            );

            assert_eq!(None, using);
            assert_eq!(
                Expr::BinaryOp {
                    left: Box::new(Expr::Identifier(Ident::new("name"))),
                    op: Eq,
                    right: Box::new(Expr::Value(number("5"))),
                },
                selection.unwrap(),
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_where_delete_with_alias_statement() {
    use self::BinaryOperator::*;

    let sql = "DELETE FROM basket AS a USING basket AS b WHERE a.id < b.id";
    match verified_stmt(sql) {
        Statement::Delete {
            table_name,
            using,
            selection,
        } => {
            assert_eq!(
                TableFactor::Table {
                    name: ObjectName(vec![Ident::new("basket")]),
                    alias: Some(TableAlias {
                        name: Ident::new("a"),
                        columns: vec![]
                    }),
                    args: None,
                    with_hints: vec![]
                },
                table_name,
            );

            assert_eq!(
                Some(TableFactor::Table {
                    name: ObjectName(vec![Ident::new("basket")]),
                    alias: Some(TableAlias {
                        name: Ident::new("b"),
                        columns: vec![]
                    }),
                    args: None,
                    with_hints: vec![]
                }),
                using
            );
            assert_eq!(
                Expr::BinaryOp {
                    left: Box::new(Expr::CompoundIdentifier(vec![
                        Ident::new("a"),
                        Ident::new("id")
                    ])),
                    op: Lt,
                    right: Box::new(Expr::CompoundIdentifier(vec![
                        Ident::new("b"),
                        Ident::new("id")
                    ])),
                },
                selection.unwrap(),
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_top_level() {
    verified_stmt("SELECT 1");
    verified_stmt("(SELECT 1)");
    verified_stmt("((SELECT 1))");
    verified_stmt("VALUES (1)");
}

#[test]
fn parse_simple_select() {
    let sql = "SELECT id, fname, lname FROM customer WHERE id = 1 LIMIT 5";
    let select = verified_only_select(sql);
    assert!(!select.distinct);
    assert_eq!(3, select.projection.len());
    let select = verified_query(sql);
    assert_eq!(Some(Expr::Value(number("5"))), select.limit);
}

#[test]
fn parse_limit_is_not_an_alias() {
    // In dialects supporting LIMIT it shouldn't be parsed as a table alias
    let ast = verified_query("SELECT id FROM customer LIMIT 1");
    assert_eq!(Some(Expr::Value(number("1"))), ast.limit);

    let ast = verified_query("SELECT 1 LIMIT 5");
    assert_eq!(Some(Expr::Value(number("5"))), ast.limit);
}

#[test]
fn parse_select_distinct() {
    let sql = "SELECT DISTINCT name FROM customer";
    let select = verified_only_select(sql);
    assert!(select.distinct);
    assert_eq!(
        &SelectItem::UnnamedExpr(Expr::Identifier(Ident::new("name"))),
        only(&select.projection)
    );
}

#[test]
fn parse_select_distinct_two_fields() {
    let sql = "SELECT DISTINCT name, id FROM customer";
    let select = verified_only_select(sql);
    assert!(select.distinct);
    assert_eq!(
        &SelectItem::UnnamedExpr(Expr::Identifier(Ident::new("name"))),
        &select.projection[0]
    );
    assert_eq!(
        &SelectItem::UnnamedExpr(Expr::Identifier(Ident::new("id"))),
        &select.projection[1]
    );
}

#[test]
fn parse_select_distinct_tuple() {
    let sql = "SELECT DISTINCT (name, id) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &vec![SelectItem::UnnamedExpr(Expr::Tuple(vec![
            Expr::Identifier(Ident::new("name")),
            Expr::Identifier(Ident::new("id")),
        ]))],
        &select.projection
    );
}

#[test]
fn parse_select_distinct_missing_paren() {
    let result = parse_sql_statements("SELECT DISTINCT (name, id FROM customer");
    assert_eq!(
        ParserError::ParserError("Expected ), found: FROM".to_string()),
        result.unwrap_err(),
    );
}

#[test]
fn parse_select_all() {
    one_statement_parses_to("SELECT ALL name FROM customer", "SELECT name FROM customer");
}

#[test]
fn parse_select_all_distinct() {
    let result = parse_sql_statements("SELECT ALL DISTINCT name FROM customer");
    assert_eq!(
        ParserError::ParserError("Cannot specify both ALL and DISTINCT".to_string()),
        result.unwrap_err(),
    );
}

#[test]
fn parse_select_into() {
    let sql = "SELECT * INTO table0 FROM table1";
    one_statement_parses_to(sql, "SELECT * INTO table0 FROM table1");
    let select = verified_only_select(sql);
    assert_eq!(
        &SelectInto {
            temporary: false,
            unlogged: false,
            table: false,
            name: ObjectName(vec![Ident::new("table0")])
        },
        only(&select.into)
    );

    let sql = "SELECT * INTO TEMPORARY UNLOGGED TABLE table0 FROM table1";
    one_statement_parses_to(
        sql,
        "SELECT * INTO TEMPORARY UNLOGGED TABLE table0 FROM table1",
    );

    // Do not allow aliases here
    let sql = "SELECT * INTO table0 asdf FROM table1";
    let result = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: asdf".to_string()),
        result.unwrap_err()
    )
}

#[test]
fn parse_select_wildcard() {
    let sql = "SELECT * FROM foo";
    let select = verified_only_select(sql);
    assert_eq!(&SelectItem::Wildcard, only(&select.projection));

    let sql = "SELECT foo.* FROM foo";
    let select = verified_only_select(sql);
    assert_eq!(
        &SelectItem::QualifiedWildcard(ObjectName(vec![Ident::new("foo")])),
        only(&select.projection)
    );

    let sql = "SELECT myschema.mytable.* FROM myschema.mytable";
    let select = verified_only_select(sql);
    assert_eq!(
        &SelectItem::QualifiedWildcard(ObjectName(vec![
            Ident::new("myschema"),
            Ident::new("mytable"),
        ])),
        only(&select.projection)
    );

    let sql = "SELECT * + * FROM foo;";
    let result = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: +".to_string()),
        result.unwrap_err(),
    );
}

#[test]
fn parse_count_wildcard() {
    verified_only_select("SELECT COUNT(*) FROM Order WHERE id = 10");

    verified_only_select(
        "SELECT COUNT(Employee.*) FROM Order JOIN Employee ON Order.employee = Employee.id",
    );
}

#[test]
fn parse_column_aliases() {
    let sql = "SELECT a.col + 1 AS newname FROM foo AS a";
    let select = verified_only_select(sql);
    if let SelectItem::ExprWithAlias {
        expr: Expr::BinaryOp {
            ref op, ref right, ..
        },
        ref alias,
    } = only(&select.projection)
    {
        assert_eq!(&BinaryOperator::Plus, op);
        assert_eq!(&Expr::Value(number("1")), right.as_ref());
        assert_eq!(&Ident::new("newname"), alias);
    } else {
        panic!("Expected ExprWithAlias")
    }

    // alias without AS is parsed correctly:
    one_statement_parses_to("SELECT a.col + 1 newname FROM foo AS a", sql);
}

#[test]
fn test_eof_after_as() {
    let res = parse_sql_statements("SELECT foo AS");
    assert_eq!(
        ParserError::ParserError("Expected an identifier after AS, found: EOF".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("SELECT 1 FROM foo AS");
    assert_eq!(
        ParserError::ParserError("Expected an identifier after AS, found: EOF".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn test_no_infix_error() {
    let res = Parser::parse_sql(&ClickHouseDialect {}, "ASSERT-URA<<");
    assert_eq!(
        ParserError::ParserError("No infix parser for token ShiftLeft".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_select_count_wildcard() {
    let sql = "SELECT COUNT(*) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("COUNT")]),
            args: vec![FunctionArg::Unnamed(FunctionArgExpr::Wildcard)],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(only(&select.projection))
    );
}

#[test]
fn parse_select_count_distinct() {
    let sql = "SELECT COUNT(DISTINCT +x) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("COUNT")]),
            args: vec![FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::UnaryOp {
                op: UnaryOperator::Plus,
                expr: Box::new(Expr::Identifier(Ident::new("x"))),
            }))],
            over: None,
            distinct: true,
            special: false,
        }),
        expr_from_projection(only(&select.projection))
    );

    one_statement_parses_to(
        "SELECT COUNT(ALL +x) FROM customer",
        "SELECT COUNT(+x) FROM customer",
    );

    let sql = "SELECT COUNT(ALL DISTINCT + x) FROM customer";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Cannot specify both ALL and DISTINCT".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_not() {
    let sql = "SELECT id FROM customer WHERE NOT salary = ''";
    let _ast = verified_only_select(sql);
    //TODO: add assertions
}

#[test]
fn parse_invalid_infix_not() {
    let res = parse_sql_statements("SELECT c FROM t WHERE c NOT (");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: NOT".to_string()),
        res.unwrap_err(),
    );
}

#[test]
fn parse_collate() {
    let sql = "SELECT name COLLATE \"de_DE\" FROM customer";
    assert_matches!(
        only(&all_dialects().verified_only_select(sql).projection),
        SelectItem::UnnamedExpr(Expr::Collate { .. })
    );
}

#[test]
fn parse_collate_after_parens() {
    let sql = "SELECT (name) COLLATE \"de_DE\" FROM customer";
    assert_matches!(
        only(&all_dialects().verified_only_select(sql).projection),
        SelectItem::UnnamedExpr(Expr::Collate { .. })
    );
}

#[test]
fn parse_select_string_predicate() {
    let sql = "SELECT id, fname, lname FROM customer \
               WHERE salary <> 'Not Provided' AND salary <> ''";
    let _ast = verified_only_select(sql);
    //TODO: add assertions
}

#[test]
fn parse_projection_nested_type() {
    let sql = "SELECT customer.address.state FROM foo";
    let _ast = verified_only_select(sql);
    //TODO: add assertions
}

#[test]
fn parse_null_in_select() {
    let sql = "SELECT NULL";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Null),
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_select_with_date_column_name() {
    let sql = "SELECT date";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Identifier(Ident {
            value: "date".into(),
            quote_style: None
        }),
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_escaped_single_quote_string_predicate() {
    use self::BinaryOperator::*;
    let sql = "SELECT id, fname, lname FROM customer \
               WHERE salary <> 'Jim''s salary'";
    let ast = verified_only_select(sql);
    assert_eq!(
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("salary"))),
            op: NotEq,
            right: Box::new(Expr::Value(Value::SingleQuotedString(
                "Jim's salary".to_string()
            )))
        }),
        ast.selection,
    );
}

#[test]
fn parse_number() {
    let expr = verified_expr("1.0");

    #[cfg(feature = "bigdecimal")]
    assert_eq!(
        expr,
        Expr::Value(Value::Number(bigdecimal::BigDecimal::from(1), false))
    );

    #[cfg(not(feature = "bigdecimal"))]
    assert_eq!(expr, Expr::Value(Value::Number("1.0".into(), false)));
}

#[test]
fn parse_compound_expr_1() {
    use self::BinaryOperator::*;
    use self::Expr::*;
    let sql = "a + b * c";
    assert_eq!(
        BinaryOp {
            left: Box::new(Identifier(Ident::new("a"))),
            op: Plus,
            right: Box::new(BinaryOp {
                left: Box::new(Identifier(Ident::new("b"))),
                op: Multiply,
                right: Box::new(Identifier(Ident::new("c")))
            })
        },
        verified_expr(sql)
    );
}

#[test]
fn parse_compound_expr_2() {
    use self::BinaryOperator::*;
    use self::Expr::*;
    let sql = "a * b + c";
    assert_eq!(
        BinaryOp {
            left: Box::new(BinaryOp {
                left: Box::new(Identifier(Ident::new("a"))),
                op: Multiply,
                right: Box::new(Identifier(Ident::new("b")))
            }),
            op: Plus,
            right: Box::new(Identifier(Ident::new("c")))
        },
        verified_expr(sql)
    );
}

#[test]
fn parse_unary_math() {
    use self::Expr::*;
    let sql = "-a + -b";
    assert_eq!(
        BinaryOp {
            left: Box::new(UnaryOp {
                op: UnaryOperator::Minus,
                expr: Box::new(Identifier(Ident::new("a"))),
            }),
            op: BinaryOperator::Plus,
            right: Box::new(UnaryOp {
                op: UnaryOperator::Minus,
                expr: Box::new(Identifier(Ident::new("b"))),
            }),
        },
        verified_expr(sql)
    );
}

#[test]
fn parse_is_null() {
    use self::Expr::*;
    let sql = "a IS NULL";
    assert_eq!(
        IsNull(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );
}

#[test]
fn parse_is_not_null() {
    use self::Expr::*;
    let sql = "a IS NOT NULL";
    assert_eq!(
        IsNotNull(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );
}

#[test]
fn parse_is_distinct_from() {
    use self::Expr::*;
    let sql = "a IS DISTINCT FROM b";
    assert_eq!(
        IsDistinctFrom(
            Box::new(Identifier(Ident::new("a"))),
            Box::new(Identifier(Ident::new("b")))
        ),
        verified_expr(sql)
    );
}
#[test]
fn parse_is_not_distinct_from() {
    use self::Expr::*;
    let sql = "a IS NOT DISTINCT FROM b";
    assert_eq!(
        IsNotDistinctFrom(
            Box::new(Identifier(Ident::new("a"))),
            Box::new(Identifier(Ident::new("b")))
        ),
        verified_expr(sql)
    );
}

#[test]
fn parse_not_precedence() {
    // NOT has higher precedence than OR/AND, so the following must parse as (NOT true) OR true
    let sql = "NOT true OR true";
    assert_matches!(
        verified_expr(sql),
        Expr::BinaryOp {
            op: BinaryOperator::Or,
            ..
        }
    );

    // But NOT has lower precedence than comparison operators, so the following parses as NOT (a IS NULL)
    let sql = "NOT a IS NULL";
    assert_matches!(
        verified_expr(sql),
        Expr::UnaryOp {
            op: UnaryOperator::Not,
            ..
        }
    );

    // NOT has lower precedence than BETWEEN, so the following parses as NOT (1 NOT BETWEEN 1 AND 2)
    let sql = "NOT 1 NOT BETWEEN 1 AND 2";
    assert_eq!(
        verified_expr(sql),
        Expr::UnaryOp {
            op: UnaryOperator::Not,
            expr: Box::new(Expr::Between {
                expr: Box::new(Expr::Value(number("1"))),
                low: Box::new(Expr::Value(number("1"))),
                high: Box::new(Expr::Value(number("2"))),
                negated: true,
            }),
        },
    );

    // NOT has lower precedence than LIKE, so the following parses as NOT ('a' NOT LIKE 'b')
    let sql = "NOT 'a' NOT LIKE 'b'";
    assert_eq!(
        verified_expr(sql),
        Expr::UnaryOp {
            op: UnaryOperator::Not,
            expr: Box::new(Expr::Like {
                expr: Box::new(Expr::Value(Value::SingleQuotedString("a".into()))),
                negated: true,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("b".into()))),
                escape_char: None
            }),
        },
    );

    // NOT has lower precedence than IN, so the following parses as NOT (a NOT IN 'a')
    let sql = "NOT a NOT IN ('a')";
    assert_eq!(
        verified_expr(sql),
        Expr::UnaryOp {
            op: UnaryOperator::Not,
            expr: Box::new(Expr::InList {
                expr: Box::new(Expr::Identifier("a".into())),
                list: vec![Expr::Value(Value::SingleQuotedString("a".into()))],
                negated: true,
            }),
        },
    );
}

#[test]
fn parse_like() {
    fn chk(negated: bool) {
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}LIKE '%a'",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::Like {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: None
            },
            select.selection.unwrap()
        );

        // Test with escape char
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}LIKE '%a' ESCAPE '\\'",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::Like {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: Some('\\')
            },
            select.selection.unwrap()
        );

        // This statement tests that LIKE and NOT LIKE have the same precedence.
        // This was previously mishandled (#81).
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}LIKE '%a' IS NULL",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::IsNull(Box::new(Expr::Like {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: None
            })),
            select.selection.unwrap()
        );
    }
    chk(false);
    chk(true);
}

#[test]
fn parse_null_like() {
    let sql = "SELECT \
            column1 LIKE NULL AS col_null, \
            NULL LIKE column1 AS null_col \
        FROM customers";
    let select = verified_only_select(sql);
    assert_eq!(
        SelectItem::ExprWithAlias {
            expr: Expr::Like {
                expr: Box::new(Expr::Identifier(Ident::new("column1"))),
                negated: false,
                pattern: Box::new(Expr::Value(Value::Null)),
                escape_char: None
            },
            alias: Ident {
                value: "col_null".to_owned(),
                quote_style: None
            }
        },
        select.projection[0]
    );
    assert_eq!(
        SelectItem::ExprWithAlias {
            expr: Expr::Like {
                expr: Box::new(Expr::Value(Value::Null)),
                negated: false,
                pattern: Box::new(Expr::Identifier(Ident::new("column1"))),
                escape_char: None
            },
            alias: Ident {
                value: "null_col".to_owned(),
                quote_style: None
            }
        },
        select.projection[1]
    );
}

#[test]
fn parse_ilike() {
    fn chk(negated: bool) {
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}ILIKE '%a'",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::ILike {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: None
            },
            select.selection.unwrap()
        );

        // Test with escape char
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}ILIKE '%a' ESCAPE '^'",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::ILike {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: Some('^')
            },
            select.selection.unwrap()
        );

        // This statement tests that ILIKE and NOT ILIKE have the same precedence.
        // This was previously mishandled (#81).
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}ILIKE '%a' IS NULL",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::IsNull(Box::new(Expr::ILike {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: None
            })),
            select.selection.unwrap()
        );
    }
    chk(false);
    chk(true);
}

#[test]
fn parse_similar_to() {
    fn chk(negated: bool) {
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}SIMILAR TO '%a'",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::SimilarTo {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: None
            },
            select.selection.unwrap()
        );

        // Test with escape char
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}SIMILAR TO '%a' ESCAPE '\\'",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::SimilarTo {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: Some('\\')
            },
            select.selection.unwrap()
        );

        // This statement tests that SIMILAR TO and NOT SIMILAR TO have the same precedence.
        let sql = &format!(
            "SELECT * FROM customers WHERE name {}SIMILAR TO '%a' ESCAPE '\\' IS NULL",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::IsNull(Box::new(Expr::SimilarTo {
                expr: Box::new(Expr::Identifier(Ident::new("name"))),
                negated,
                pattern: Box::new(Expr::Value(Value::SingleQuotedString("%a".to_string()))),
                escape_char: Some('\\')
            })),
            select.selection.unwrap()
        );
    }
    chk(false);
    chk(true);
}

#[test]
fn parse_in_list() {
    fn chk(negated: bool) {
        let sql = &format!(
            "SELECT * FROM customers WHERE segment {}IN ('HIGH', 'MED')",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::InList {
                expr: Box::new(Expr::Identifier(Ident::new("segment"))),
                list: vec![
                    Expr::Value(Value::SingleQuotedString("HIGH".to_string())),
                    Expr::Value(Value::SingleQuotedString("MED".to_string())),
                ],
                negated,
            },
            select.selection.unwrap()
        );
    }
    chk(false);
    chk(true);
}

#[test]
fn parse_in_subquery() {
    let sql = "SELECT * FROM customers WHERE segment IN (SELECT segm FROM bar)";
    let select = verified_only_select(sql);
    assert_eq!(
        Expr::InSubquery {
            expr: Box::new(Expr::Identifier(Ident::new("segment"))),
            subquery: Box::new(verified_query("SELECT segm FROM bar")),
            negated: false,
        },
        select.selection.unwrap()
    );
}

#[test]
fn parse_in_unnest() {
    fn chk(negated: bool) {
        let sql = &format!(
            "SELECT * FROM customers WHERE segment {}IN UNNEST(expr)",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::InUnnest {
                expr: Box::new(Expr::Identifier(Ident::new("segment"))),
                array_expr: Box::new(verified_expr("expr")),
                negated,
            },
            select.selection.unwrap()
        );
    }
    chk(false);
    chk(true);
}

#[test]
fn parse_in_error() {
    // <expr> IN <expr> is no valid
    let sql = "SELECT * FROM customers WHERE segment in segment";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected (, found: segment".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_string_agg() {
    let sql = "SELECT a || b";

    let select = verified_only_select(sql);
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("a"))),
            op: BinaryOperator::StringConcat,
            right: Box::new(Expr::Identifier(Ident::new("b"))),
        }),
        select.projection[0]
    );
}

#[test]
fn parse_bitwise_ops() {
    let bitwise_ops = &[
        ("^", BinaryOperator::BitwiseXor),
        ("|", BinaryOperator::BitwiseOr),
        ("&", BinaryOperator::BitwiseAnd),
    ];

    for (str_op, op) in bitwise_ops {
        let select = verified_only_select(&format!("SELECT a {} b", &str_op));
        assert_eq!(
            SelectItem::UnnamedExpr(Expr::BinaryOp {
                left: Box::new(Expr::Identifier(Ident::new("a"))),
                op: op.clone(),
                right: Box::new(Expr::Identifier(Ident::new("b"))),
            }),
            select.projection[0]
        );
    }
}

#[test]
fn parse_binary_any() {
    let select = verified_only_select("SELECT a = ANY(b)");
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("a"))),
            op: BinaryOperator::Eq,
            right: Box::new(Expr::AnyOp(Box::new(Expr::Identifier(Ident::new("b"))))),
        }),
        select.projection[0]
    );
}

#[test]
fn parse_binary_all() {
    let select = verified_only_select("SELECT a = ALL(b)");
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("a"))),
            op: BinaryOperator::Eq,
            right: Box::new(Expr::AllOp(Box::new(Expr::Identifier(Ident::new("b"))))),
        }),
        select.projection[0]
    );
}

#[test]
fn parse_logical_xor() {
    let sql = "SELECT true XOR true, false XOR false, true XOR false, false XOR true";
    let select = verified_only_select(sql);
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Value(Value::Boolean(true))),
            op: BinaryOperator::Xor,
            right: Box::new(Expr::Value(Value::Boolean(true))),
        }),
        select.projection[0]
    );
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Value(Value::Boolean(false))),
            op: BinaryOperator::Xor,
            right: Box::new(Expr::Value(Value::Boolean(false))),
        }),
        select.projection[1]
    );
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Value(Value::Boolean(true))),
            op: BinaryOperator::Xor,
            right: Box::new(Expr::Value(Value::Boolean(false))),
        }),
        select.projection[2]
    );
    assert_eq!(
        SelectItem::UnnamedExpr(Expr::BinaryOp {
            left: Box::new(Expr::Value(Value::Boolean(false))),
            op: BinaryOperator::Xor,
            right: Box::new(Expr::Value(Value::Boolean(true))),
        }),
        select.projection[3]
    );
}

#[test]
fn parse_between() {
    fn chk(negated: bool) {
        let sql = &format!(
            "SELECT * FROM customers WHERE age {}BETWEEN 25 AND 32",
            if negated { "NOT " } else { "" }
        );
        let select = verified_only_select(sql);
        assert_eq!(
            Expr::Between {
                expr: Box::new(Expr::Identifier(Ident::new("age"))),
                low: Box::new(Expr::Value(number("25"))),
                high: Box::new(Expr::Value(number("32"))),
                negated,
            },
            select.selection.unwrap()
        );
    }
    chk(false);
    chk(true);
}

#[test]
fn parse_between_with_expr() {
    use self::BinaryOperator::*;
    let sql = "SELECT * FROM t WHERE 1 BETWEEN 1 + 2 AND 3 + 4 IS NULL";
    let select = verified_only_select(sql);
    assert_eq!(
        Expr::IsNull(Box::new(Expr::Between {
            expr: Box::new(Expr::Value(number("1"))),
            low: Box::new(Expr::BinaryOp {
                left: Box::new(Expr::Value(number("1"))),
                op: Plus,
                right: Box::new(Expr::Value(number("2"))),
            }),
            high: Box::new(Expr::BinaryOp {
                left: Box::new(Expr::Value(number("3"))),
                op: Plus,
                right: Box::new(Expr::Value(number("4"))),
            }),
            negated: false,
        })),
        select.selection.unwrap()
    );

    let sql = "SELECT * FROM t WHERE 1 = 1 AND 1 + x BETWEEN 1 AND 2";
    let select = verified_only_select(sql);
    assert_eq!(
        Expr::BinaryOp {
            left: Box::new(Expr::BinaryOp {
                left: Box::new(Expr::Value(number("1"))),
                op: BinaryOperator::Eq,
                right: Box::new(Expr::Value(number("1"))),
            }),
            op: BinaryOperator::And,
            right: Box::new(Expr::Between {
                expr: Box::new(Expr::BinaryOp {
                    left: Box::new(Expr::Value(number("1"))),
                    op: BinaryOperator::Plus,
                    right: Box::new(Expr::Identifier(Ident::new("x"))),
                }),
                low: Box::new(Expr::Value(number("1"))),
                high: Box::new(Expr::Value(number("2"))),
                negated: false,
            }),
        },
        select.selection.unwrap(),
    )
}

#[test]
fn parse_tuples() {
    let sql = "SELECT (1, 2), (1), ('foo', 3, baz)";
    let select = verified_only_select(sql);
    assert_eq!(
        vec![
            SelectItem::UnnamedExpr(Expr::Tuple(vec![
                Expr::Value(number("1")),
                Expr::Value(number("2"))
            ])),
            SelectItem::UnnamedExpr(Expr::Nested(Box::new(Expr::Value(number("1"))))),
            SelectItem::UnnamedExpr(Expr::Tuple(vec![
                Expr::Value(Value::SingleQuotedString("foo".into())),
                Expr::Value(number("3")),
                Expr::Identifier(Ident::new("baz"))
            ]))
        ],
        select.projection
    );
}

#[test]
fn parse_tuple_invalid() {
    let sql = "select (1";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected ), found: EOF".to_string()),
        res.unwrap_err()
    );

    let sql = "select (), 2";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected an expression:, found: )".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_select_order_by() {
    fn chk(sql: &str) {
        let select = verified_query(sql);
        assert_eq!(
            vec![
                OrderByExpr {
                    expr: Expr::Identifier(Ident::new("lname")),
                    asc: Some(true),
                    nulls_first: None,
                },
                OrderByExpr {
                    expr: Expr::Identifier(Ident::new("fname")),
                    asc: Some(false),
                    nulls_first: None,
                },
                OrderByExpr {
                    expr: Expr::Identifier(Ident::new("id")),
                    asc: None,
                    nulls_first: None,
                },
            ],
            select.order_by
        );
    }
    chk("SELECT id, fname, lname FROM customer WHERE id < 5 ORDER BY lname ASC, fname DESC, id");
    // make sure ORDER is not treated as an alias
    chk("SELECT id, fname, lname FROM customer ORDER BY lname ASC, fname DESC, id");
    chk("SELECT 1 AS lname, 2 AS fname, 3 AS id, 4 ORDER BY lname ASC, fname DESC, id");
}

#[test]
fn parse_select_order_by_limit() {
    let sql = "SELECT id, fname, lname FROM customer WHERE id < 5 \
               ORDER BY lname ASC, fname DESC LIMIT 2";
    let select = verified_query(sql);
    assert_eq!(
        vec![
            OrderByExpr {
                expr: Expr::Identifier(Ident::new("lname")),
                asc: Some(true),
                nulls_first: None,
            },
            OrderByExpr {
                expr: Expr::Identifier(Ident::new("fname")),
                asc: Some(false),
                nulls_first: None,
            },
        ],
        select.order_by
    );
    assert_eq!(Some(Expr::Value(number("2"))), select.limit);
}

#[test]
fn parse_select_order_by_nulls_order() {
    let sql = "SELECT id, fname, lname FROM customer WHERE id < 5 \
               ORDER BY lname ASC NULLS FIRST, fname DESC NULLS LAST LIMIT 2";
    let select = verified_query(sql);
    assert_eq!(
        vec![
            OrderByExpr {
                expr: Expr::Identifier(Ident::new("lname")),
                asc: Some(true),
                nulls_first: Some(true),
            },
            OrderByExpr {
                expr: Expr::Identifier(Ident::new("fname")),
                asc: Some(false),
                nulls_first: Some(false),
            },
        ],
        select.order_by
    );
    assert_eq!(Some(Expr::Value(number("2"))), select.limit);
}

#[test]
fn parse_select_group_by() {
    let sql = "SELECT id, fname, lname FROM customer GROUP BY lname, fname";
    let select = verified_only_select(sql);
    assert_eq!(
        vec![
            Expr::Identifier(Ident::new("lname")),
            Expr::Identifier(Ident::new("fname")),
        ],
        select.group_by
    );

    // Tuples can also be in the set
    one_statement_parses_to(
        "SELECT id, fname, lname FROM customer GROUP BY (lname, fname)",
        "SELECT id, fname, lname FROM customer GROUP BY (lname, fname)",
    );
}

#[test]
fn parse_select_group_by_grouping_sets() {
    let dialects = TestedDialects {
        dialects: vec![Box::new(PostgreSqlDialect {})],
    };
    let sql =
        "SELECT brand, size, sum(sales) FROM items_sold GROUP BY size, GROUPING SETS ((brand), (size), ())";
    let select = dialects.verified_only_select(sql);
    assert_eq!(
        vec![
            Expr::Identifier(Ident::new("size")),
            Expr::GroupingSets(vec![
                vec![Expr::Identifier(Ident::new("brand"))],
                vec![Expr::Identifier(Ident::new("size"))],
                vec![],
            ])
        ],
        select.group_by
    );
}

#[test]
fn parse_select_group_by_rollup() {
    let dialects = TestedDialects {
        dialects: vec![Box::new(PostgreSqlDialect {})],
    };
    let sql = "SELECT brand, size, sum(sales) FROM items_sold GROUP BY size, ROLLUP (brand, size)";
    let select = dialects.verified_only_select(sql);
    assert_eq!(
        vec![
            Expr::Identifier(Ident::new("size")),
            Expr::Rollup(vec![
                vec![Expr::Identifier(Ident::new("brand"))],
                vec![Expr::Identifier(Ident::new("size"))],
            ])
        ],
        select.group_by
    );
}

#[test]
fn parse_select_group_by_cube() {
    let dialects = TestedDialects {
        dialects: vec![Box::new(PostgreSqlDialect {})],
    };
    let sql = "SELECT brand, size, sum(sales) FROM items_sold GROUP BY size, CUBE (brand, size)";
    let select = dialects.verified_only_select(sql);
    assert_eq!(
        vec![
            Expr::Identifier(Ident::new("size")),
            Expr::Cube(vec![
                vec![Expr::Identifier(Ident::new("brand"))],
                vec![Expr::Identifier(Ident::new("size"))],
            ])
        ],
        select.group_by
    );
}

#[test]
fn parse_select_having() {
    let sql = "SELECT foo FROM bar GROUP BY foo HAVING COUNT(*) > 1";
    let select = verified_only_select(sql);
    assert_eq!(
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Function(Function {
                name: ObjectName(vec![Ident::new("COUNT")]),
                args: vec![FunctionArg::Unnamed(FunctionArgExpr::Wildcard)],
                over: None,
                distinct: false,
                special: false,
            })),
            op: BinaryOperator::Gt,
            right: Box::new(Expr::Value(number("1")))
        }),
        select.having
    );

    let sql = "SELECT 'foo' HAVING 1 = 1";
    let select = verified_only_select(sql);
    assert!(select.having.is_some());
}

#[cfg(feature = "bigdecimal")]
#[test]
fn parse_select_qualify() {
    let sql = "SELECT i, p, o FROM qt QUALIFY ROW_NUMBER() OVER (PARTITION BY p ORDER BY o) = 1";
    let select = verified_only_select(sql);
    assert_eq!(
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Function(Function {
                name: ObjectName(vec![Ident::new("ROW_NUMBER")]),
                args: vec![],
                over: Some(WindowSpec {
                    partition_by: vec![Expr::Identifier(Ident::new("p"))],
                    order_by: vec![OrderByExpr {
                        expr: Expr::Identifier(Ident::new("o")),
                        asc: None,
                        nulls_first: None
                    }],
                    window_frame: None
                }),
                distinct: false,
                special: false
            })),
            op: BinaryOperator::Eq,
            right: Box::new(Expr::Value(number("1")))
        }),
        select.qualify
    );

    let sql = "SELECT i, p, o, ROW_NUMBER() OVER (PARTITION BY p ORDER BY o) AS row_num FROM qt QUALIFY row_num = 1";
    let select = verified_only_select(sql);
    assert_eq!(
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("row_num"))),
            op: BinaryOperator::Eq,
            right: Box::new(Expr::Value(number("1")))
        }),
        select.qualify
    );
}

#[test]
fn parse_limit_accepts_all() {
    one_statement_parses_to(
        "SELECT id, fname, lname FROM customer WHERE id = 1 LIMIT ALL",
        "SELECT id, fname, lname FROM customer WHERE id = 1",
    );
}

#[test]
fn parse_limit_my_sql_syntax() {
    one_statement_parses_to(
        "SELECT id, fname, lname FROM customer LIMIT 5, 10",
        "SELECT id, fname, lname FROM customer LIMIT 5 OFFSET 10",
    );
}

#[test]
fn parse_cast() {
    let sql = "SELECT CAST(id AS BIGINT) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Cast {
            expr: Box::new(Expr::Identifier(Ident::new("id"))),
            data_type: DataType::BigInt(None)
        },
        expr_from_projection(only(&select.projection))
    );

    let sql = "SELECT CAST(id AS TINYINT) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Cast {
            expr: Box::new(Expr::Identifier(Ident::new("id"))),
            data_type: DataType::TinyInt(None)
        },
        expr_from_projection(only(&select.projection))
    );

    one_statement_parses_to(
        "SELECT CAST(id AS BIGINT) FROM customer",
        "SELECT CAST(id AS BIGINT) FROM customer",
    );

    verified_stmt("SELECT CAST(id AS NUMERIC) FROM customer");

    one_statement_parses_to(
        "SELECT CAST(id AS DEC) FROM customer",
        "SELECT CAST(id AS NUMERIC) FROM customer",
    );

    one_statement_parses_to(
        "SELECT CAST(id AS DECIMAL) FROM customer",
        "SELECT CAST(id AS NUMERIC) FROM customer",
    );

    let sql = "SELECT CAST(id AS NVARCHAR(50)) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Cast {
            expr: Box::new(Expr::Identifier(Ident::new("id"))),
            data_type: DataType::Nvarchar(Some(50))
        },
        expr_from_projection(only(&select.projection))
    );
}

#[test]
fn parse_try_cast() {
    let sql = "SELECT TRY_CAST(id AS BIGINT) FROM customer";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::TryCast {
            expr: Box::new(Expr::Identifier(Ident::new("id"))),
            data_type: DataType::BigInt(None)
        },
        expr_from_projection(only(&select.projection))
    );
    one_statement_parses_to(
        "SELECT TRY_CAST(id AS BIGINT) FROM customer",
        "SELECT TRY_CAST(id AS BIGINT) FROM customer",
    );

    verified_stmt("SELECT TRY_CAST(id AS NUMERIC) FROM customer");

    one_statement_parses_to(
        "SELECT TRY_CAST(id AS DEC) FROM customer",
        "SELECT TRY_CAST(id AS NUMERIC) FROM customer",
    );

    one_statement_parses_to(
        "SELECT TRY_CAST(id AS DECIMAL) FROM customer",
        "SELECT TRY_CAST(id AS NUMERIC) FROM customer",
    );
}

#[test]
fn parse_extract() {
    let sql = "SELECT EXTRACT(YEAR FROM d)";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Extract {
            field: DateTimeField::Year,
            expr: Box::new(Expr::Identifier(Ident::new("d"))),
        },
        expr_from_projection(only(&select.projection)),
    );

    one_statement_parses_to("SELECT EXTRACT(year from d)", "SELECT EXTRACT(YEAR FROM d)");

    verified_stmt("SELECT EXTRACT(MONTH FROM d)");
    verified_stmt("SELECT EXTRACT(WEEK FROM d)");
    verified_stmt("SELECT EXTRACT(DAY FROM d)");
    verified_stmt("SELECT EXTRACT(HOUR FROM d)");
    verified_stmt("SELECT EXTRACT(MINUTE FROM d)");
    verified_stmt("SELECT EXTRACT(SECOND FROM d)");
    verified_stmt("SELECT EXTRACT(CENTURY FROM d)");
    verified_stmt("SELECT EXTRACT(DECADE FROM d)");
    verified_stmt("SELECT EXTRACT(DOW FROM d)");
    verified_stmt("SELECT EXTRACT(DOY FROM d)");
    verified_stmt("SELECT EXTRACT(EPOCH FROM d)");
    verified_stmt("SELECT EXTRACT(ISODOW FROM d)");
    verified_stmt("SELECT EXTRACT(ISOYEAR FROM d)");
    verified_stmt("SELECT EXTRACT(JULIAN FROM d)");
    verified_stmt("SELECT EXTRACT(MICROSECONDS FROM d)");
    verified_stmt("SELECT EXTRACT(MILLENIUM FROM d)");
    verified_stmt("SELECT EXTRACT(MILLISECONDS FROM d)");
    verified_stmt("SELECT EXTRACT(QUARTER FROM d)");
    verified_stmt("SELECT EXTRACT(TIMEZONE FROM d)");
    verified_stmt("SELECT EXTRACT(TIMEZONE_HOUR FROM d)");
    verified_stmt("SELECT EXTRACT(TIMEZONE_MINUTE FROM d)");

    let res = parse_sql_statements("SELECT EXTRACT(MILLISECOND FROM d)");
    assert_eq!(
        ParserError::ParserError("Expected date/time field, found: MILLISECOND".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_listagg() {
    let sql = "SELECT LISTAGG(DISTINCT dateid, ', ' ON OVERFLOW TRUNCATE '%' WITHOUT COUNT) \
               WITHIN GROUP (ORDER BY id, username)";
    let select = verified_only_select(sql);

    verified_stmt("SELECT LISTAGG(sellerid) WITHIN GROUP (ORDER BY dateid)");
    verified_stmt("SELECT LISTAGG(dateid)");
    verified_stmt("SELECT LISTAGG(DISTINCT dateid)");
    verified_stmt("SELECT LISTAGG(dateid ON OVERFLOW ERROR)");
    verified_stmt("SELECT LISTAGG(dateid ON OVERFLOW TRUNCATE N'...' WITH COUNT)");
    verified_stmt("SELECT LISTAGG(dateid ON OVERFLOW TRUNCATE X'deadbeef' WITH COUNT)");

    let expr = Box::new(Expr::Identifier(Ident::new("dateid")));
    let on_overflow = Some(ListAggOnOverflow::Truncate {
        filler: Some(Box::new(Expr::Value(Value::SingleQuotedString(
            "%".to_string(),
        )))),
        with_count: false,
    });
    let within_group = vec![
        OrderByExpr {
            expr: Expr::Identifier(Ident {
                value: "id".to_string(),
                quote_style: None,
            }),
            asc: None,
            nulls_first: None,
        },
        OrderByExpr {
            expr: Expr::Identifier(Ident {
                value: "username".to_string(),
                quote_style: None,
            }),
            asc: None,
            nulls_first: None,
        },
    ];
    assert_eq!(
        &Expr::ListAgg(ListAgg {
            distinct: true,
            expr,
            separator: Some(Box::new(Expr::Value(Value::SingleQuotedString(
                ", ".to_string()
            )))),
            on_overflow,
            within_group
        }),
        expr_from_projection(only(&select.projection))
    );
}

#[test]
fn parse_create_table() {
    let sql = "CREATE TABLE uk_cities (\
               name VARCHAR(100) NOT NULL,\
               lat DOUBLE NULL,\
               lng DOUBLE,
               constrained INT NULL CONSTRAINT pkey PRIMARY KEY NOT NULL UNIQUE CHECK (constrained > 0),
               ref INT REFERENCES othertable (a, b),\
               ref2 INT references othertable2 on delete cascade on update no action,\
               constraint fkey foreign key (lat) references othertable3 (lat) on delete restrict,\
               constraint fkey2 foreign key (lat) references othertable4(lat) on delete no action on update restrict, \
               foreign key (lat) references othertable4(lat) on update set default on delete cascade, \
               FOREIGN KEY (lng) REFERENCES othertable4 (longitude) ON UPDATE SET NULL
               )";
    let ast = one_statement_parses_to(
        sql,
        "CREATE TABLE uk_cities (\
         name CHARACTER VARYING(100) NOT NULL, \
         lat DOUBLE NULL, \
         lng DOUBLE, \
         constrained INT NULL CONSTRAINT pkey PRIMARY KEY NOT NULL UNIQUE CHECK (constrained > 0), \
         ref INT REFERENCES othertable (a, b), \
         ref2 INT REFERENCES othertable2 ON DELETE CASCADE ON UPDATE NO ACTION, \
         CONSTRAINT fkey FOREIGN KEY (lat) REFERENCES othertable3(lat) ON DELETE RESTRICT, \
         CONSTRAINT fkey2 FOREIGN KEY (lat) REFERENCES othertable4(lat) ON DELETE NO ACTION ON UPDATE RESTRICT, \
         FOREIGN KEY (lat) REFERENCES othertable4(lat) ON DELETE CASCADE ON UPDATE SET DEFAULT, \
         FOREIGN KEY (lng) REFERENCES othertable4(longitude) ON UPDATE SET NULL)",
    );
    match ast {
        Statement::CreateTable {
            name,
            columns,
            constraints,
            with_options,
            if_not_exists: false,
            external: false,
            file_format: None,
            location: None,
            ..
        } => {
            assert_eq!("uk_cities", name.to_string());
            assert_eq!(
                columns,
                vec![
                    ColumnDef {
                        name: "name".into(),
                        data_type: DataType::Varchar(Some(100)),
                        collation: None,
                        options: vec![ColumnOptionDef {
                            name: None,
                            option: ColumnOption::NotNull
                        }],
                    },
                    ColumnDef {
                        name: "lat".into(),
                        data_type: DataType::Double,
                        collation: None,
                        options: vec![ColumnOptionDef {
                            name: None,
                            option: ColumnOption::Null
                        }],
                    },
                    ColumnDef {
                        name: "lng".into(),
                        data_type: DataType::Double,
                        collation: None,
                        options: vec![],
                    },
                    ColumnDef {
                        name: "constrained".into(),
                        data_type: DataType::Int(None),
                        collation: None,
                        options: vec![
                            ColumnOptionDef {
                                name: None,
                                option: ColumnOption::Null
                            },
                            ColumnOptionDef {
                                name: Some("pkey".into()),
                                option: ColumnOption::Unique { is_primary: true }
                            },
                            ColumnOptionDef {
                                name: None,
                                option: ColumnOption::NotNull
                            },
                            ColumnOptionDef {
                                name: None,
                                option: ColumnOption::Unique { is_primary: false },
                            },
                            ColumnOptionDef {
                                name: None,
                                option: ColumnOption::Check(verified_expr("constrained > 0")),
                            }
                        ],
                    },
                    ColumnDef {
                        name: "ref".into(),
                        data_type: DataType::Int(None),
                        collation: None,
                        options: vec![ColumnOptionDef {
                            name: None,
                            option: ColumnOption::ForeignKey {
                                foreign_table: ObjectName(vec!["othertable".into()]),
                                referred_columns: vec!["a".into(), "b".into(),],
                                on_delete: None,
                                on_update: None,
                            }
                        }]
                    },
                    ColumnDef {
                        name: "ref2".into(),
                        data_type: DataType::Int(None),
                        collation: None,
                        options: vec![ColumnOptionDef {
                            name: None,
                            option: ColumnOption::ForeignKey {
                                foreign_table: ObjectName(vec!["othertable2".into()]),
                                referred_columns: vec![],
                                on_delete: Some(ReferentialAction::Cascade),
                                on_update: Some(ReferentialAction::NoAction),
                            }
                        },]
                    }
                ]
            );
            assert_eq!(
                constraints,
                vec![
                    TableConstraint::ForeignKey {
                        name: Some("fkey".into()),
                        columns: vec!["lat".into()],
                        foreign_table: ObjectName(vec!["othertable3".into()]),
                        referred_columns: vec!["lat".into()],
                        on_delete: Some(ReferentialAction::Restrict),
                        on_update: None
                    },
                    TableConstraint::ForeignKey {
                        name: Some("fkey2".into()),
                        columns: vec!["lat".into()],
                        foreign_table: ObjectName(vec!["othertable4".into()]),
                        referred_columns: vec!["lat".into()],
                        on_delete: Some(ReferentialAction::NoAction),
                        on_update: Some(ReferentialAction::Restrict)
                    },
                    TableConstraint::ForeignKey {
                        name: None,
                        columns: vec!["lat".into()],
                        foreign_table: ObjectName(vec!["othertable4".into()]),
                        referred_columns: vec!["lat".into()],
                        on_delete: Some(ReferentialAction::Cascade),
                        on_update: Some(ReferentialAction::SetDefault)
                    },
                    TableConstraint::ForeignKey {
                        name: None,
                        columns: vec!["lng".into()],
                        foreign_table: ObjectName(vec!["othertable4".into()]),
                        referred_columns: vec!["longitude".into()],
                        on_delete: None,
                        on_update: Some(ReferentialAction::SetNull)
                    },
                ]
            );
            assert_eq!(with_options, vec![]);
        }
        _ => unreachable!(),
    }

    let res = parse_sql_statements("CREATE TABLE t (a int NOT NULL GARBAGE)");
    assert!(res
        .unwrap_err()
        .to_string()
        .contains("Expected \',\' or \')\' after column definition, found: GARBAGE"));

    let res = parse_sql_statements("CREATE TABLE t (a int NOT NULL CONSTRAINT foo)");
    assert!(res
        .unwrap_err()
        .to_string()
        .contains("Expected constraint details after CONSTRAINT <name>"));
}

#[test]
fn parse_create_table_hive_array() {
    // Parsing [] type arrays does not work in MsSql since [ is used in is_delimited_identifier_start
    let dialects = TestedDialects {
        dialects: vec![Box::new(PostgreSqlDialect {}), Box::new(HiveDialect {})],
    };
    let sql = "CREATE TABLE IF NOT EXISTS something (key int, val array<int>)";
    match dialects.one_statement_parses_to(
        sql,
        "CREATE TABLE IF NOT EXISTS something (key INT, val INT[])",
    ) {
        Statement::CreateTable {
            if_not_exists,
            name,
            columns,
            ..
        } => {
            assert!(if_not_exists);
            assert_eq!(name, ObjectName(vec!["something".into()]));
            assert_eq!(
                columns,
                vec![
                    ColumnDef {
                        name: Ident::new("key"),
                        data_type: DataType::Int(None),
                        collation: None,
                        options: vec![],
                    },
                    ColumnDef {
                        name: Ident::new("val"),
                        data_type: DataType::Array(Box::new(DataType::Int(None))),
                        collation: None,
                        options: vec![],
                    },
                ],
            )
        }
        _ => unreachable!(),
    }

    let res = parse_sql_statements("CREATE TABLE IF NOT EXISTS something (key int, val array<int)");
    assert!(res
        .unwrap_err()
        .to_string()
        .contains("Expected >, found: )"));
}

#[test]
fn parse_create_table_with_multiple_on_delete_in_constraint_fails() {
    parse_sql_statements(
        "\
        create table X (\
            y_id int, \
            foreign key (y_id) references Y (id) on delete cascade on update cascade on delete no action\
        )",
    )
        .expect_err("should have failed");
}

#[test]
fn parse_create_table_with_multiple_on_delete_fails() {
    parse_sql_statements(
        "\
        create table X (\
            y_id int references Y (id) \
            on delete cascade on update cascade on delete no action\
        )",
    )
    .expect_err("should have failed");
}

#[test]
fn parse_assert() {
    let sql = "ASSERT (SELECT COUNT(*) FROM my_table) > 0";
    let ast = one_statement_parses_to(sql, "ASSERT (SELECT COUNT(*) FROM my_table) > 0");
    match ast {
        Statement::Assert {
            condition: _condition,
            message,
        } => {
            assert_eq!(message, None);
        }
        _ => unreachable!(),
    }
}

#[test]
#[allow(clippy::collapsible_match)]
fn parse_assert_message() {
    let sql = "ASSERT (SELECT COUNT(*) FROM my_table) > 0 AS 'No rows in my_table'";
    let ast = one_statement_parses_to(
        sql,
        "ASSERT (SELECT COUNT(*) FROM my_table) > 0 AS 'No rows in my_table'",
    );
    match ast {
        Statement::Assert {
            condition: _condition,
            message: Some(message),
        } => {
            match message {
                Expr::Value(Value::SingleQuotedString(s)) => assert_eq!(s, "No rows in my_table"),
                _ => unreachable!(),
            };
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_schema() {
    let sql = "CREATE SCHEMA X";

    match verified_stmt(sql) {
        Statement::CreateSchema { schema_name, .. } => {
            assert_eq!(schema_name.to_string(), "X".to_owned())
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_drop_schema() {
    let sql = "DROP SCHEMA X";

    match verified_stmt(sql) {
        Statement::Drop { object_type, .. } => assert_eq!(object_type, ObjectType::Schema),
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_table_as() {
    let sql = "CREATE TABLE t AS SELECT * FROM a";

    match verified_stmt(sql) {
        Statement::CreateTable { name, query, .. } => {
            assert_eq!(name.to_string(), "t".to_string());
            assert_eq!(query, Some(Box::new(verified_query("SELECT * FROM a"))));
        }
        _ => unreachable!(),
    }

    // BigQuery allows specifying table schema in CTAS
    // ANSI SQL and PostgreSQL let you only specify the list of columns
    // (without data types) in a CTAS, but we have yet to support that.
    let sql = "CREATE TABLE t (a INT, b INT) AS SELECT 1 AS b, 2 AS a";
    match verified_stmt(sql) {
        Statement::CreateTable { columns, query, .. } => {
            assert_eq!(columns.len(), 2);
            assert_eq!(columns[0].to_string(), "a INT".to_string());
            assert_eq!(columns[1].to_string(), "b INT".to_string());
            assert_eq!(
                query,
                Some(Box::new(verified_query("SELECT 1 AS b, 2 AS a")))
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_table_on_cluster() {
    // Using single-quote literal to define current cluster
    let sql = "CREATE TABLE t ON CLUSTER '{cluster}' (a INT, b INT)";
    match verified_stmt(sql) {
        Statement::CreateTable { on_cluster, .. } => {
            assert_eq!(on_cluster.unwrap(), "{cluster}".to_string());
        }
        _ => unreachable!(),
    }

    // Using explicitly declared cluster name
    let sql = "CREATE TABLE t ON CLUSTER my_cluster (a INT, b INT)";
    match verified_stmt(sql) {
        Statement::CreateTable { on_cluster, .. } => {
            assert_eq!(on_cluster.unwrap(), "my_cluster".to_string());
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_or_replace_table() {
    let sql = "CREATE OR REPLACE TABLE t (a INT)";

    match verified_stmt(sql) {
        Statement::CreateTable {
            name, or_replace, ..
        } => {
            assert_eq!(name.to_string(), "t".to_string());
            assert!(or_replace);
        }
        _ => unreachable!(),
    }

    let sql = "CREATE TABLE t (a INT, b INT) AS SELECT 1 AS b, 2 AS a";
    match verified_stmt(sql) {
        Statement::CreateTable { columns, query, .. } => {
            assert_eq!(columns.len(), 2);
            assert_eq!(columns[0].to_string(), "a INT".to_string());
            assert_eq!(columns[1].to_string(), "b INT".to_string());
            assert_eq!(
                query,
                Some(Box::new(verified_query("SELECT 1 AS b, 2 AS a")))
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_table_with_on_delete_on_update_2in_any_order() -> Result<(), ParserError> {
    let sql = |options: &str| -> String {
        format!("create table X (y_id int references Y (id) {})", options)
    };

    parse_sql_statements(&sql("on update cascade on delete no action"))?;
    parse_sql_statements(&sql("on delete cascade on update cascade"))?;
    parse_sql_statements(&sql("on update no action"))?;
    parse_sql_statements(&sql("on delete restrict"))?;

    Ok(())
}

#[test]
fn parse_create_table_with_options() {
    let sql = "CREATE TABLE t (c INT) WITH (foo = 'bar', a = 123)";
    match verified_stmt(sql) {
        Statement::CreateTable { with_options, .. } => {
            assert_eq!(
                vec![
                    SqlOption {
                        name: "foo".into(),
                        value: Value::SingleQuotedString("bar".into())
                    },
                    SqlOption {
                        name: "a".into(),
                        value: number("123")
                    },
                ],
                with_options
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_table_clone() {
    let sql = "CREATE OR REPLACE TABLE a CLONE a_tmp";
    match verified_stmt(sql) {
        Statement::CreateTable { name, clone, .. } => {
            assert_eq!(ObjectName(vec![Ident::new("a")]), name);
            assert_eq!(Some(ObjectName(vec![(Ident::new("a_tmp"))])), clone)
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_table_trailing_comma() {
    let sql = "CREATE TABLE foo (bar int,)";
    all_dialects().one_statement_parses_to(sql, "CREATE TABLE foo (bar INT)");
}

#[test]
fn parse_create_external_table() {
    let sql = "CREATE EXTERNAL TABLE uk_cities (\
               name VARCHAR(100) NOT NULL,\
               lat DOUBLE NULL,\
               lng DOUBLE)\
               STORED AS TEXTFILE LOCATION '/tmp/example.csv'";
    let ast = one_statement_parses_to(
        sql,
        "CREATE EXTERNAL TABLE uk_cities (\
         name CHARACTER VARYING(100) NOT NULL, \
         lat DOUBLE NULL, \
         lng DOUBLE) \
         STORED AS TEXTFILE LOCATION '/tmp/example.csv'",
    );
    match ast {
        Statement::CreateTable {
            name,
            columns,
            constraints,
            with_options,
            if_not_exists,
            external,
            file_format,
            location,
            ..
        } => {
            assert_eq!("uk_cities", name.to_string());
            assert_eq!(
                columns,
                vec![
                    ColumnDef {
                        name: "name".into(),
                        data_type: DataType::Varchar(Some(100)),
                        collation: None,
                        options: vec![ColumnOptionDef {
                            name: None,
                            option: ColumnOption::NotNull
                        }],
                    },
                    ColumnDef {
                        name: "lat".into(),
                        data_type: DataType::Double,
                        collation: None,
                        options: vec![ColumnOptionDef {
                            name: None,
                            option: ColumnOption::Null
                        }],
                    },
                    ColumnDef {
                        name: "lng".into(),
                        data_type: DataType::Double,
                        collation: None,
                        options: vec![],
                    },
                ]
            );
            assert!(constraints.is_empty());

            assert!(external);
            assert_eq!(FileFormat::TEXTFILE, file_format.unwrap());
            assert_eq!("/tmp/example.csv", location.unwrap());

            assert_eq!(with_options, vec![]);
            assert!(!if_not_exists);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_or_replace_external_table() {
    // Supported by at least Snowflake
    // https://docs.snowflake.com/en/sql-reference/sql/create-external-table.html
    let sql = "CREATE OR REPLACE EXTERNAL TABLE uk_cities (\
               name VARCHAR(100) NOT NULL)\
               STORED AS TEXTFILE LOCATION '/tmp/example.csv'";
    let ast = one_statement_parses_to(
        sql,
        "CREATE OR REPLACE EXTERNAL TABLE uk_cities (\
         name CHARACTER VARYING(100) NOT NULL) \
         STORED AS TEXTFILE LOCATION '/tmp/example.csv'",
    );
    match ast {
        Statement::CreateTable {
            name,
            columns,
            constraints,
            with_options,
            if_not_exists,
            external,
            file_format,
            location,
            or_replace,
            ..
        } => {
            assert_eq!("uk_cities", name.to_string());
            assert_eq!(
                columns,
                vec![ColumnDef {
                    name: "name".into(),
                    data_type: DataType::Varchar(Some(100)),
                    collation: None,
                    options: vec![ColumnOptionDef {
                        name: None,
                        option: ColumnOption::NotNull
                    }],
                },]
            );
            assert!(constraints.is_empty());

            assert!(external);
            assert_eq!(FileFormat::TEXTFILE, file_format.unwrap());
            assert_eq!("/tmp/example.csv", location.unwrap());

            assert_eq!(with_options, vec![]);
            assert!(!if_not_exists);
            assert!(or_replace);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_external_table_lowercase() {
    let sql = "create external table uk_cities (\
               name varchar(100) not null,\
               lat double null,\
               lng double)\
               stored as parquet location '/tmp/example.csv'";
    let ast = one_statement_parses_to(
        sql,
        "CREATE EXTERNAL TABLE uk_cities (\
         name CHARACTER VARYING(100) NOT NULL, \
         lat DOUBLE NULL, \
         lng DOUBLE) \
         STORED AS PARQUET LOCATION '/tmp/example.csv'",
    );
    assert_matches!(ast, Statement::CreateTable { .. });
}

#[test]
fn parse_alter_table() {
    let add_column = "ALTER TABLE tab ADD COLUMN foo TEXT;";
    match one_statement_parses_to(add_column, "ALTER TABLE tab ADD COLUMN foo TEXT") {
        Statement::AlterTable {
            name,
            operation: AlterTableOperation::AddColumn { column_def },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("foo", column_def.name.to_string());
            assert_eq!("TEXT", column_def.data_type.to_string());
        }
        _ => unreachable!(),
    };

    let rename_table = "ALTER TABLE tab RENAME TO new_tab";
    match verified_stmt(rename_table) {
        Statement::AlterTable {
            name,
            operation: AlterTableOperation::RenameTable { table_name },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("new_tab", table_name.to_string())
        }
        _ => unreachable!(),
    };

    let rename_column = "ALTER TABLE tab RENAME COLUMN foo TO new_foo";
    match verified_stmt(rename_column) {
        Statement::AlterTable {
            name,
            operation:
                AlterTableOperation::RenameColumn {
                    old_column_name,
                    new_column_name,
                },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!(old_column_name.to_string(), "foo");
            assert_eq!(new_column_name.to_string(), "new_foo");
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_alter_table_constraints() {
    check_one("CONSTRAINT address_pkey PRIMARY KEY (address_id)");
    check_one("CONSTRAINT uk_task UNIQUE (report_date, task_id)");
    check_one(
        "CONSTRAINT customer_address_id_fkey FOREIGN KEY (address_id) \
         REFERENCES public.address(address_id)",
    );
    check_one("CONSTRAINT ck CHECK (rtrim(ltrim(REF_CODE)) <> '')");

    check_one("PRIMARY KEY (foo, bar)");
    check_one("UNIQUE (id)");
    check_one("FOREIGN KEY (foo, bar) REFERENCES AnotherTable(foo, bar)");
    check_one("CHECK (end_date > start_date OR end_date IS NULL)");

    fn check_one(constraint_text: &str) {
        match verified_stmt(&format!("ALTER TABLE tab ADD {}", constraint_text)) {
            Statement::AlterTable {
                name,
                operation: AlterTableOperation::AddConstraint(constraint),
            } => {
                assert_eq!("tab", name.to_string());
                assert_eq!(constraint_text, constraint.to_string());
            }
            _ => unreachable!(),
        }
        verified_stmt(&format!("CREATE TABLE foo (id INT, {})", constraint_text));
    }
}

#[test]
fn parse_alter_table_drop_column() {
    check_one("DROP COLUMN IF EXISTS is_active CASCADE");
    one_statement_parses_to(
        "ALTER TABLE tab DROP IF EXISTS is_active CASCADE",
        "ALTER TABLE tab DROP COLUMN IF EXISTS is_active CASCADE",
    );
    one_statement_parses_to(
        "ALTER TABLE tab DROP is_active CASCADE",
        "ALTER TABLE tab DROP COLUMN is_active CASCADE",
    );

    fn check_one(constraint_text: &str) {
        match verified_stmt(&format!("ALTER TABLE tab {}", constraint_text)) {
            Statement::AlterTable {
                name,
                operation:
                    AlterTableOperation::DropColumn {
                        column_name,
                        if_exists,
                        cascade,
                    },
            } => {
                assert_eq!("tab", name.to_string());
                assert_eq!("is_active", column_name.to_string());
                assert!(if_exists);
                assert!(cascade);
            }
            _ => unreachable!(),
        }
    }
}

#[test]
fn parse_alter_table_alter_column() {
    let alter_stmt = "ALTER TABLE tab";
    match verified_stmt(&format!(
        "{} ALTER COLUMN is_active SET NOT NULL",
        alter_stmt
    )) {
        Statement::AlterTable {
            name,
            operation: AlterTableOperation::AlterColumn { column_name, op },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("is_active", column_name.to_string());
            assert_eq!(op, AlterColumnOperation::SetNotNull {});
        }
        _ => unreachable!(),
    }

    one_statement_parses_to(
        "ALTER TABLE tab ALTER is_active DROP NOT NULL",
        "ALTER TABLE tab ALTER COLUMN is_active DROP NOT NULL",
    );

    match verified_stmt(&format!(
        "{} ALTER COLUMN is_active SET DEFAULT false",
        alter_stmt
    )) {
        Statement::AlterTable {
            name,
            operation: AlterTableOperation::AlterColumn { column_name, op },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("is_active", column_name.to_string());
            assert_eq!(
                op,
                AlterColumnOperation::SetDefault {
                    value: Expr::Value(Value::Boolean(false))
                }
            );
        }
        _ => unreachable!(),
    }

    match verified_stmt(&format!(
        "{} ALTER COLUMN is_active DROP DEFAULT",
        alter_stmt
    )) {
        Statement::AlterTable {
            name,
            operation: AlterTableOperation::AlterColumn { column_name, op },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("is_active", column_name.to_string());
            assert_eq!(op, AlterColumnOperation::DropDefault {});
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_alter_table_alter_column_type() {
    let alter_stmt = "ALTER TABLE tab";
    match verified_stmt("ALTER TABLE tab ALTER COLUMN is_active SET DATA TYPE TEXT") {
        Statement::AlterTable {
            name,
            operation: AlterTableOperation::AlterColumn { column_name, op },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("is_active", column_name.to_string());
            assert_eq!(
                op,
                AlterColumnOperation::SetDataType {
                    data_type: DataType::Text,
                    using: None,
                }
            );
        }
        _ => unreachable!(),
    }

    let res = Parser::parse_sql(
        &GenericDialect {},
        &format!("{} ALTER COLUMN is_active TYPE TEXT", alter_stmt),
    );
    assert_eq!(
        ParserError::ParserError("Expected SET/DROP NOT NULL, SET DEFAULT, SET DATA TYPE after ALTER COLUMN, found: TYPE".to_string()),
        res.unwrap_err()
    );

    let res = Parser::parse_sql(
        &GenericDialect {},
        &format!(
            "{} ALTER COLUMN is_active SET DATA TYPE TEXT USING 'text'",
            alter_stmt
        ),
    );
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: USING".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_alter_table_drop_constraint() {
    let alter_stmt = "ALTER TABLE tab";
    match verified_stmt("ALTER TABLE tab DROP CONSTRAINT constraint_name CASCADE") {
        Statement::AlterTable {
            name,
            operation:
                AlterTableOperation::DropConstraint {
                    name: constr_name,
                    if_exists,
                    cascade,
                },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("constraint_name", constr_name.to_string());
            assert!(!if_exists);
            assert!(cascade);
        }
        _ => unreachable!(),
    }
    match verified_stmt("ALTER TABLE tab DROP CONSTRAINT IF EXISTS constraint_name") {
        Statement::AlterTable {
            name,
            operation:
                AlterTableOperation::DropConstraint {
                    name: constr_name,
                    if_exists,
                    cascade,
                },
        } => {
            assert_eq!("tab", name.to_string());
            assert_eq!("constraint_name", constr_name.to_string());
            assert!(if_exists);
            assert!(!cascade);
        }
        _ => unreachable!(),
    }

    let res = Parser::parse_sql(
        &GenericDialect {},
        &format!("{} DROP CONSTRAINT is_active TEXT", alter_stmt),
    );
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: TEXT".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_bad_constraint() {
    let res = parse_sql_statements("ALTER TABLE tab ADD");
    assert_eq!(
        ParserError::ParserError("Expected identifier, found: EOF".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("CREATE TABLE tab (foo int,");
    assert_eq!(
        ParserError::ParserError(
            "Expected column name or constraint definition, found: EOF".to_string()
        ),
        res.unwrap_err()
    );
}

#[test]
fn parse_scalar_function_in_projection() {
    let names = vec!["sqrt", "foo"];

    for function_name in names {
        // like SELECT sqrt(id) FROM foo
        let sql = dbg!(format!("SELECT {}(id) FROM foo", function_name));
        let select = verified_only_select(&sql);
        assert_eq!(
            &Expr::Function(Function {
                name: ObjectName(vec![Ident::new(function_name)]),
                args: vec![FunctionArg::Unnamed(FunctionArgExpr::Expr(
                    Expr::Identifier(Ident::new("id"))
                ))],
                over: None,
                distinct: false,
                special: false,
            }),
            expr_from_projection(only(&select.projection))
        );
    }
}

fn run_explain_analyze(query: &str, expected_verbose: bool, expected_analyze: bool) {
    match verified_stmt(query) {
        Statement::Explain {
            describe_alias: _,
            analyze,
            verbose,
            statement,
        } => {
            assert_eq!(verbose, expected_verbose);
            assert_eq!(analyze, expected_analyze);
            assert_eq!("SELECT sqrt(id) FROM foo", statement.to_string());
        }
        _ => panic!("Unexpected Statement, must be Explain"),
    }
}

#[test]
fn parse_explain_table() {
    let validate_explain = |query: &str, expected_describe_alias: bool| match verified_stmt(query) {
        Statement::ExplainTable {
            describe_alias,
            table_name,
        } => {
            assert_eq!(describe_alias, expected_describe_alias);
            assert_eq!("test_identifier", table_name.to_string());
        }
        _ => panic!("Unexpected Statement, must be ExplainTable"),
    };

    validate_explain("EXPLAIN test_identifier", false);
    validate_explain("DESCRIBE test_identifier", true);
}

#[test]
fn parse_explain_analyze_with_simple_select() {
    // Describe is an alias for EXPLAIN
    run_explain_analyze("DESCRIBE SELECT sqrt(id) FROM foo", false, false);

    run_explain_analyze("EXPLAIN SELECT sqrt(id) FROM foo", false, false);
    run_explain_analyze("EXPLAIN VERBOSE SELECT sqrt(id) FROM foo", true, false);
    run_explain_analyze("EXPLAIN ANALYZE SELECT sqrt(id) FROM foo", false, true);
    run_explain_analyze(
        "EXPLAIN ANALYZE VERBOSE SELECT sqrt(id) FROM foo",
        true,
        true,
    );
}

#[test]
fn parse_named_argument_function() {
    let sql = "SELECT FUN(a => '1', b => '2') FROM foo";
    let select = verified_only_select(sql);

    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("FUN")]),
            args: vec![
                FunctionArg::Named {
                    name: Ident::new("a"),
                    arg: FunctionArgExpr::Expr(Expr::Value(Value::SingleQuotedString(
                        "1".to_owned()
                    ))),
                },
                FunctionArg::Named {
                    name: Ident::new("b"),
                    arg: FunctionArgExpr::Expr(Expr::Value(Value::SingleQuotedString(
                        "2".to_owned()
                    ))),
                },
            ],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(only(&select.projection))
    );
}

#[test]
fn parse_window_functions() {
    let sql = "SELECT row_number() OVER (ORDER BY dt DESC), \
               sum(foo) OVER (PARTITION BY a, b ORDER BY c, d \
               ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW), \
               avg(bar) OVER (ORDER BY a \
               RANGE BETWEEN 1 PRECEDING AND 1 FOLLOWING), \
               max(baz) OVER (ORDER BY a \
               ROWS UNBOUNDED PRECEDING), \
               sum(qux) OVER (ORDER BY a \
               GROUPS BETWEEN 1 PRECEDING AND 1 FOLLOWING) \
               FROM foo";
    let select = verified_only_select(sql);
    assert_eq!(5, select.projection.len());
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("row_number")]),
            args: vec![],
            over: Some(WindowSpec {
                partition_by: vec![],
                order_by: vec![OrderByExpr {
                    expr: Expr::Identifier(Ident::new("dt")),
                    asc: Some(false),
                    nulls_first: None,
                }],
                window_frame: None,
            }),
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[0])
    );
}

#[test]
fn parse_aggregate_with_group_by() {
    let sql = "SELECT a, COUNT(1), MIN(b), MAX(b) FROM foo GROUP BY a";
    let _ast = verified_only_select(sql);
    //TODO: assertions
}

#[test]
fn parse_literal_decimal() {
    // These numbers were explicitly chosen to not roundtrip if represented as
    // f64s (i.e., as 64-bit binary floating point numbers).
    let sql = "SELECT 0.300000000000000004, 9007199254740993.0";
    let select = verified_only_select(sql);
    assert_eq!(2, select.projection.len());
    assert_eq!(
        &Expr::Value(number("0.300000000000000004")),
        expr_from_projection(&select.projection[0]),
    );
    assert_eq!(
        &Expr::Value(number("9007199254740993.0")),
        expr_from_projection(&select.projection[1]),
    )
}

#[test]
fn parse_literal_string() {
    let sql = "SELECT 'one', N'national string', X'deadBEEF'";
    let select = verified_only_select(sql);
    assert_eq!(3, select.projection.len());
    assert_eq!(
        &Expr::Value(Value::SingleQuotedString("one".to_string())),
        expr_from_projection(&select.projection[0])
    );
    assert_eq!(
        &Expr::Value(Value::NationalStringLiteral("national string".to_string())),
        expr_from_projection(&select.projection[1])
    );
    assert_eq!(
        &Expr::Value(Value::HexStringLiteral("deadBEEF".to_string())),
        expr_from_projection(&select.projection[2])
    );

    one_statement_parses_to("SELECT x'deadBEEF'", "SELECT X'deadBEEF'");
}

#[test]
fn parse_literal_date() {
    let sql = "SELECT DATE '1999-01-01'";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::TypedString {
            data_type: DataType::Date,
            value: "1999-01-01".into()
        },
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_literal_time() {
    let sql = "SELECT TIME '01:23:34'";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::TypedString {
            data_type: DataType::Time,
            value: "01:23:34".into()
        },
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_literal_datetime() {
    let sql = "SELECT DATETIME '1999-01-01 01:23:34.45'";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::TypedString {
            data_type: DataType::Datetime,
            value: "1999-01-01 01:23:34.45".into()
        },
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_literal_timestamp_without_time_zone() {
    let sql = "SELECT TIMESTAMP '1999-01-01 01:23:34'";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::TypedString {
            data_type: DataType::Timestamp,
            value: "1999-01-01 01:23:34".into()
        },
        expr_from_projection(only(&select.projection)),
    );

    one_statement_parses_to(
        "SELECT TIMESTAMP WITHOUT TIME ZONE '1999-01-01 01:23:34'",
        sql,
    );
}

#[test]
fn parse_literal_timestamp_with_time_zone() {
    let sql = "SELECT TIMESTAMPTZ '1999-01-01 01:23:34Z'";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::TypedString {
            data_type: DataType::TimestampTz,
            value: "1999-01-01 01:23:34Z".into()
        },
        expr_from_projection(only(&select.projection)),
    );

    one_statement_parses_to(
        "SELECT TIMESTAMP WITH TIME ZONE '1999-01-01 01:23:34Z'",
        sql,
    );
}

#[test]
fn parse_literal_interval() {
    let sql = "SELECT INTERVAL '1-1' YEAR TO MONTH";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(Value::SingleQuotedString(String::from("1-1")))),
            leading_field: Some(DateTimeField::Year),
            leading_precision: None,
            last_field: Some(DateTimeField::Month),
            fractional_seconds_precision: None,
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL '01:01.01' MINUTE (5) TO SECOND (5)";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(Value::SingleQuotedString(String::from(
                "01:01.01"
            )))),
            leading_field: Some(DateTimeField::Minute),
            leading_precision: Some(5),
            last_field: Some(DateTimeField::Second),
            fractional_seconds_precision: Some(5),
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL '1' SECOND (5, 4)";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(Value::SingleQuotedString(String::from("1")))),
            leading_field: Some(DateTimeField::Second),
            leading_precision: Some(5),
            last_field: None,
            fractional_seconds_precision: Some(4),
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL '10' HOUR";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(Value::SingleQuotedString(String::from("10")))),
            leading_field: Some(DateTimeField::Hour),
            leading_precision: None,
            last_field: None,
            fractional_seconds_precision: None,
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL 5 DAY";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(number("5"))),
            leading_field: Some(DateTimeField::Day),
            leading_precision: None,
            last_field: None,
            fractional_seconds_precision: None,
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL 1 + 1 DAY";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::BinaryOp {
                left: Box::new(Expr::Value(number("1"))),
                op: BinaryOperator::Plus,
                right: Box::new(Expr::Value(number("1")))
            }),
            leading_field: Some(DateTimeField::Day),
            leading_precision: None,
            last_field: None,
            fractional_seconds_precision: None,
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL '10' HOUR (1)";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(Value::SingleQuotedString(String::from("10")))),
            leading_field: Some(DateTimeField::Hour),
            leading_precision: Some(1),
            last_field: None,
            fractional_seconds_precision: None,
        }),
        expr_from_projection(only(&select.projection)),
    );

    let sql = "SELECT INTERVAL '1 DAY'";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Value(Value::Interval {
            value: Box::new(Expr::Value(Value::SingleQuotedString(String::from(
                "1 DAY"
            )))),
            leading_field: None,
            leading_precision: None,
            last_field: None,
            fractional_seconds_precision: None,
        }),
        expr_from_projection(only(&select.projection)),
    );

    let result = parse_sql_statements("SELECT INTERVAL '1' SECOND TO SECOND");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: SECOND".to_string()),
        result.unwrap_err(),
    );

    let result = parse_sql_statements("SELECT INTERVAL '10' HOUR (1) TO HOUR (2)");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: (".to_string()),
        result.unwrap_err(),
    );

    verified_only_select("SELECT INTERVAL '1' YEAR");
    verified_only_select("SELECT INTERVAL '1' MONTH");
    verified_only_select("SELECT INTERVAL '1' DAY");
    verified_only_select("SELECT INTERVAL '1' HOUR");
    verified_only_select("SELECT INTERVAL '1' MINUTE");
    verified_only_select("SELECT INTERVAL '1' SECOND");
    verified_only_select("SELECT INTERVAL '1' YEAR TO MONTH");
    verified_only_select("SELECT INTERVAL '1' DAY TO HOUR");
    verified_only_select("SELECT INTERVAL '1' DAY TO MINUTE");
    verified_only_select("SELECT INTERVAL '1' DAY TO SECOND");
    verified_only_select("SELECT INTERVAL '1' HOUR TO MINUTE");
    verified_only_select("SELECT INTERVAL '1' HOUR TO SECOND");
    verified_only_select("SELECT INTERVAL '1' MINUTE TO SECOND");
    verified_only_select("SELECT INTERVAL '1 YEAR'");
    verified_only_select("SELECT INTERVAL '1 YEAR' AS one_year");
    one_statement_parses_to(
        "SELECT INTERVAL '1 YEAR' one_year",
        "SELECT INTERVAL '1 YEAR' AS one_year",
    );
}

#[test]
fn parse_at_timezone() {
    let zero = Expr::Value(number("0"));
    let sql = "SELECT FROM_UNIXTIME(0) AT TIME ZONE 'UTC-06:00' FROM t";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::AtTimeZone {
            timestamp: Box::new(Expr::Function(Function {
                name: ObjectName(vec![Ident {
                    value: "FROM_UNIXTIME".to_string(),
                    quote_style: None
                }]),
                args: vec![FunctionArg::Unnamed(FunctionArgExpr::Expr(zero.clone()))],
                over: None,
                distinct: false,
                special: false,
            })),
            time_zone: "UTC-06:00".to_string()
        },
        expr_from_projection(only(&select.projection)),
    );

    let sql = r#"SELECT DATE_FORMAT(FROM_UNIXTIME(0) AT TIME ZONE 'UTC-06:00', '%Y-%m-%dT%H') AS "hour" FROM t"#;
    let select = verified_only_select(sql);
    assert_eq!(
        &SelectItem::ExprWithAlias {
            expr: Expr::Function(Function {
                name: ObjectName(vec![Ident {
                    value: "DATE_FORMAT".to_string(),
                    quote_style: None,
                },],),
                args: vec![
                    FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::AtTimeZone {
                        timestamp: Box::new(Expr::Function(Function {
                            name: ObjectName(vec![Ident {
                                value: "FROM_UNIXTIME".to_string(),
                                quote_style: None,
                            },],),
                            args: vec![FunctionArg::Unnamed(FunctionArgExpr::Expr(zero,),),],
                            over: None,
                            distinct: false,
                            special: false
                        },)),
                        time_zone: "UTC-06:00".to_string(),
                    },),),
                    FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::Value(
                        Value::SingleQuotedString("%Y-%m-%dT%H".to_string(),),
                    ),),),
                ],
                over: None,
                distinct: false,
                special: false
            },),
            alias: Ident {
                value: "hour".to_string(),
                quote_style: Some('"',),
            },
        },
        only(&select.projection),
    );
}

#[test]
fn parse_simple_math_expr_plus() {
    let sql = "SELECT a + b, 2 + a, 2.5 + a, a_f + b_f, 2 + a_f, 2.5 + a_f FROM c";
    verified_only_select(sql);
}

#[test]
fn parse_simple_math_expr_minus() {
    let sql = "SELECT a - b, 2 - a, 2.5 - a, a_f - b_f, 2 - a_f, 2.5 - a_f FROM c";
    verified_only_select(sql);
}

#[test]
fn parse_table_function() {
    let select = verified_only_select("SELECT * FROM TABLE(FUN('1')) AS a");

    match only(select.from).relation {
        TableFactor::TableFunction { expr, alias } => {
            let expected_expr = Expr::Function(Function {
                name: ObjectName(vec![Ident::new("FUN")]),
                args: vec![FunctionArg::Unnamed(FunctionArgExpr::Expr(Expr::Value(
                    Value::SingleQuotedString("1".to_owned()),
                )))],
                over: None,
                distinct: false,
                special: false,
            });
            assert_eq!(expr, expected_expr);
            assert_eq!(alias, table_alias("a"))
        }
        _ => panic!("Expecting TableFactor::TableFunction"),
    }

    let res = parse_sql_statements("SELECT * FROM TABLE '1' AS a");
    assert_eq!(
        ParserError::ParserError("Expected (, found: \'1\'".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("SELECT * FROM TABLE (FUN(a) AS a");
    assert_eq!(
        ParserError::ParserError("Expected ), found: AS".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_unnest() {
    fn chk(
        alias: bool,
        with_offset: bool,
        with_offset_alias: bool,
        dialects: &TestedDialects,
        want: Vec<TableWithJoins>,
    ) {
        let sql = &format!(
            "SELECT * FROM UNNEST(expr){}{}{}",
            if alias { " AS numbers" } else { "" },
            if with_offset { " WITH OFFSET" } else { "" },
            if with_offset_alias {
                " AS with_offset_alias"
            } else {
                ""
            },
        );
        let select = dialects.verified_only_select(sql);
        assert_eq!(select.from, want);
    }
    let dialects = TestedDialects {
        dialects: vec![Box::new(BigQueryDialect {}), Box::new(GenericDialect {})],
    };
    // 1. both Alias and WITH OFFSET clauses.
    chk(
        true,
        true,
        false,
        &dialects,
        vec![TableWithJoins {
            relation: TableFactor::UNNEST {
                alias: Some(TableAlias {
                    name: Ident::new("numbers"),
                    columns: vec![],
                }),
                array_expr: Box::new(Expr::Identifier(Ident::new("expr"))),
                with_offset: true,
                with_offset_alias: None,
            },
            joins: vec![],
        }],
    );
    // 2. neither Alias nor WITH OFFSET clause.
    chk(
        false,
        false,
        false,
        &dialects,
        vec![TableWithJoins {
            relation: TableFactor::UNNEST {
                alias: None,
                array_expr: Box::new(Expr::Identifier(Ident::new("expr"))),
                with_offset: false,
                with_offset_alias: None,
            },
            joins: vec![],
        }],
    );
    // 3. Alias but no WITH OFFSET clause.
    chk(
        false,
        true,
        false,
        &dialects,
        vec![TableWithJoins {
            relation: TableFactor::UNNEST {
                alias: None,
                array_expr: Box::new(Expr::Identifier(Ident::new("expr"))),
                with_offset: true,
                with_offset_alias: None,
            },
            joins: vec![],
        }],
    );
    // 4. WITH OFFSET but no Alias.
    chk(
        true,
        false,
        false,
        &dialects,
        vec![TableWithJoins {
            relation: TableFactor::UNNEST {
                alias: Some(TableAlias {
                    name: Ident::new("numbers"),
                    columns: vec![],
                }),
                array_expr: Box::new(Expr::Identifier(Ident::new("expr"))),
                with_offset: false,
                with_offset_alias: None,
            },
            joins: vec![],
        }],
    );
    // 5. WITH OFFSET and WITH OFFSET Alias
    chk(
        true,
        false,
        true,
        &dialects,
        vec![TableWithJoins {
            relation: TableFactor::UNNEST {
                alias: Some(TableAlias {
                    name: Ident::new("numbers"),
                    columns: vec![],
                }),
                array_expr: Box::new(Expr::Identifier(Ident::new("expr"))),
                with_offset: false,
                with_offset_alias: Some(Ident::new("with_offset_alias")),
            },
            joins: vec![],
        }],
    );
}

#[test]
fn parse_delimited_identifiers() {
    // check that quoted identifiers in any position remain quoted after serialization
    let select = verified_only_select(
        r#"SELECT "alias"."bar baz", "myfun"(), "simple id" AS "column alias" FROM "a table" AS "alias""#,
    );
    // check FROM
    match only(select.from).relation {
        TableFactor::Table {
            name,
            alias,
            args,
            with_hints,
        } => {
            assert_eq!(vec![Ident::with_quote('"', "a table")], name.0);
            assert_eq!(Ident::with_quote('"', "alias"), alias.unwrap().name);
            assert!(args.is_none());
            assert!(with_hints.is_empty());
        }
        _ => panic!("Expecting TableFactor::Table"),
    }
    // check SELECT
    assert_eq!(3, select.projection.len());
    assert_eq!(
        &Expr::CompoundIdentifier(vec![
            Ident::with_quote('"', "alias"),
            Ident::with_quote('"', "bar baz")
        ]),
        expr_from_projection(&select.projection[0]),
    );
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::with_quote('"', "myfun")]),
            args: vec![],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[1]),
    );
    match &select.projection[2] {
        SelectItem::ExprWithAlias { expr, alias } => {
            assert_eq!(&Expr::Identifier(Ident::with_quote('"', "simple id")), expr);
            assert_eq!(&Ident::with_quote('"', "column alias"), alias);
        }
        _ => panic!("Expected ExprWithAlias"),
    }

    verified_stmt(r#"CREATE TABLE "foo" ("bar" "int")"#);
    verified_stmt(r#"ALTER TABLE foo ADD CONSTRAINT "bar" PRIMARY KEY (baz)"#);
    //TODO verified_stmt(r#"UPDATE foo SET "bar" = 5"#);
}

#[test]
fn parse_parens() {
    use self::BinaryOperator::*;
    use self::Expr::*;
    let sql = "(a + b) - (c + d)";
    assert_eq!(
        BinaryOp {
            left: Box::new(Nested(Box::new(BinaryOp {
                left: Box::new(Identifier(Ident::new("a"))),
                op: Plus,
                right: Box::new(Identifier(Ident::new("b")))
            }))),
            op: Minus,
            right: Box::new(Nested(Box::new(BinaryOp {
                left: Box::new(Identifier(Ident::new("c"))),
                op: Plus,
                right: Box::new(Identifier(Ident::new("d")))
            })))
        },
        verified_expr(sql)
    );
}

#[test]
fn parse_searched_case_expr() {
    let sql = "SELECT CASE WHEN bar IS NULL THEN 'null' WHEN bar = 0 THEN '=0' WHEN bar >= 0 THEN '>=0' ELSE '<0' END FROM foo";
    use self::BinaryOperator::*;
    use self::Expr::{BinaryOp, Case, Identifier, IsNull};
    let select = verified_only_select(sql);
    assert_eq!(
        &Case {
            operand: None,
            conditions: vec![
                IsNull(Box::new(Identifier(Ident::new("bar")))),
                BinaryOp {
                    left: Box::new(Identifier(Ident::new("bar"))),
                    op: Eq,
                    right: Box::new(Expr::Value(number("0")))
                },
                BinaryOp {
                    left: Box::new(Identifier(Ident::new("bar"))),
                    op: GtEq,
                    right: Box::new(Expr::Value(number("0")))
                }
            ],
            results: vec![
                Expr::Value(Value::SingleQuotedString("null".to_string())),
                Expr::Value(Value::SingleQuotedString("=0".to_string())),
                Expr::Value(Value::SingleQuotedString(">=0".to_string()))
            ],
            else_result: Some(Box::new(Expr::Value(Value::SingleQuotedString(
                "<0".to_string()
            ))))
        },
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_simple_case_expr() {
    // ANSI calls a CASE expression with an operand "<simple case>"
    let sql = "SELECT CASE foo WHEN 1 THEN 'Y' ELSE 'N' END";
    let select = verified_only_select(sql);
    use self::Expr::{Case, Identifier};
    assert_eq!(
        &Case {
            operand: Some(Box::new(Identifier(Ident::new("foo")))),
            conditions: vec![Expr::Value(number("1"))],
            results: vec![Expr::Value(Value::SingleQuotedString("Y".to_string())),],
            else_result: Some(Box::new(Expr::Value(Value::SingleQuotedString(
                "N".to_string()
            ))))
        },
        expr_from_projection(only(&select.projection)),
    );
}

#[test]
fn parse_from_advanced() {
    let sql = "SELECT * FROM fn(1, 2) AS foo, schema.bar AS bar WITH (NOLOCK)";
    let _select = verified_only_select(sql);
}

#[test]
fn parse_nullary_table_valued_function() {
    let sql = "SELECT * FROM fn()";
    let _select = verified_only_select(sql);
}

#[test]
fn parse_implicit_join() {
    let sql = "SELECT * FROM t1, t2";
    let select = verified_only_select(sql);
    assert_eq!(
        vec![
            TableWithJoins {
                relation: TableFactor::Table {
                    name: ObjectName(vec!["t1".into()]),
                    alias: None,
                    args: None,
                    with_hints: vec![],
                },
                joins: vec![],
            },
            TableWithJoins {
                relation: TableFactor::Table {
                    name: ObjectName(vec!["t2".into()]),
                    alias: None,
                    args: None,
                    with_hints: vec![],
                },
                joins: vec![],
            }
        ],
        select.from,
    );

    let sql = "SELECT * FROM t1a NATURAL JOIN t1b, t2a NATURAL JOIN t2b";
    let select = verified_only_select(sql);
    assert_eq!(
        vec![
            TableWithJoins {
                relation: TableFactor::Table {
                    name: ObjectName(vec!["t1a".into()]),
                    alias: None,
                    args: None,
                    with_hints: vec![],
                },
                joins: vec![Join {
                    relation: TableFactor::Table {
                        name: ObjectName(vec!["t1b".into()]),
                        alias: None,
                        args: None,
                        with_hints: vec![],
                    },
                    join_operator: JoinOperator::Inner(JoinConstraint::Natural),
                }]
            },
            TableWithJoins {
                relation: TableFactor::Table {
                    name: ObjectName(vec!["t2a".into()]),
                    alias: None,
                    args: None,
                    with_hints: vec![],
                },
                joins: vec![Join {
                    relation: TableFactor::Table {
                        name: ObjectName(vec!["t2b".into()]),
                        alias: None,
                        args: None,
                        with_hints: vec![],
                    },
                    join_operator: JoinOperator::Inner(JoinConstraint::Natural),
                }]
            }
        ],
        select.from,
    );
}

#[test]
fn parse_cross_join() {
    let sql = "SELECT * FROM t1 CROSS JOIN t2";
    let select = verified_only_select(sql);
    assert_eq!(
        Join {
            relation: TableFactor::Table {
                name: ObjectName(vec![Ident::new("t2")]),
                alias: None,
                args: None,
                with_hints: vec![],
            },
            join_operator: JoinOperator::CrossJoin
        },
        only(only(select.from).joins),
    );
}

#[test]
fn parse_joins_on() {
    fn join_with_constraint(
        relation: impl Into<String>,
        alias: Option<TableAlias>,
        f: impl Fn(JoinConstraint) -> JoinOperator,
    ) -> Join {
        Join {
            relation: TableFactor::Table {
                name: ObjectName(vec![Ident::new(relation.into())]),
                alias,
                args: None,
                with_hints: vec![],
            },
            join_operator: f(JoinConstraint::On(Expr::BinaryOp {
                left: Box::new(Expr::Identifier("c1".into())),
                op: BinaryOperator::Eq,
                right: Box::new(Expr::Identifier("c2".into())),
            })),
        }
    }
    // Test parsing of aliases
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 JOIN t2 AS foo ON c1 = c2").from).joins,
        vec![join_with_constraint(
            "t2",
            table_alias("foo"),
            JoinOperator::Inner
        )]
    );
    one_statement_parses_to(
        "SELECT * FROM t1 JOIN t2 foo ON c1 = c2",
        "SELECT * FROM t1 JOIN t2 AS foo ON c1 = c2",
    );
    // Test parsing of different join operators
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 JOIN t2 ON c1 = c2").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::Inner)]
    );
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 LEFT JOIN t2 ON c1 = c2").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::LeftOuter)]
    );
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 RIGHT JOIN t2 ON c1 = c2").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::RightOuter)]
    );
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 FULL JOIN t2 ON c1 = c2").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::FullOuter)]
    );
}

#[test]
fn parse_joins_using() {
    fn join_with_constraint(
        relation: impl Into<String>,
        alias: Option<TableAlias>,
        f: impl Fn(JoinConstraint) -> JoinOperator,
    ) -> Join {
        Join {
            relation: TableFactor::Table {
                name: ObjectName(vec![Ident::new(relation.into())]),
                alias,
                args: None,
                with_hints: vec![],
            },
            join_operator: f(JoinConstraint::Using(vec!["c1".into()])),
        }
    }
    // Test parsing of aliases
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 JOIN t2 AS foo USING(c1)").from).joins,
        vec![join_with_constraint(
            "t2",
            table_alias("foo"),
            JoinOperator::Inner
        )]
    );
    one_statement_parses_to(
        "SELECT * FROM t1 JOIN t2 foo USING(c1)",
        "SELECT * FROM t1 JOIN t2 AS foo USING(c1)",
    );
    // Test parsing of different join operators
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 JOIN t2 USING(c1)").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::Inner)]
    );
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 LEFT JOIN t2 USING(c1)").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::LeftOuter)]
    );
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 RIGHT JOIN t2 USING(c1)").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::RightOuter)]
    );
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 FULL JOIN t2 USING(c1)").from).joins,
        vec![join_with_constraint("t2", None, JoinOperator::FullOuter)]
    );
}

#[test]
fn parse_natural_join() {
    fn natural_join(f: impl Fn(JoinConstraint) -> JoinOperator, alias: Option<TableAlias>) -> Join {
        Join {
            relation: TableFactor::Table {
                name: ObjectName(vec![Ident::new("t2")]),
                alias,
                args: None,
                with_hints: vec![],
            },
            join_operator: f(JoinConstraint::Natural),
        }
    }

    // if not specified, inner join as default
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 NATURAL JOIN t2").from).joins,
        vec![natural_join(JoinOperator::Inner, None)]
    );
    // left join explicitly
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 NATURAL LEFT JOIN t2").from).joins,
        vec![natural_join(JoinOperator::LeftOuter, None)]
    );

    // right join explicitly
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 NATURAL RIGHT JOIN t2").from).joins,
        vec![natural_join(JoinOperator::RightOuter, None)]
    );

    // full join explicitly
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 NATURAL FULL JOIN t2").from).joins,
        vec![natural_join(JoinOperator::FullOuter, None)]
    );

    // natural join another table with alias
    assert_eq!(
        only(&verified_only_select("SELECT * FROM t1 NATURAL JOIN t2 AS t3").from).joins,
        vec![natural_join(JoinOperator::Inner, table_alias("t3"))]
    );

    let sql = "SELECT * FROM t1 natural";
    assert_eq!(
        ParserError::ParserError("Expected a join type after NATURAL, found: EOF".to_string()),
        parse_sql_statements(sql).unwrap_err(),
    );
}

#[test]
fn parse_complex_join() {
    let sql = "SELECT c1, c2 FROM t1, t4 JOIN t2 ON t2.c = t1.c LEFT JOIN t3 USING(q, c) WHERE t4.c = t1.c";
    verified_only_select(sql);
}

#[test]
fn parse_join_nesting() {
    let sql = "SELECT * FROM a NATURAL JOIN (b NATURAL JOIN (c NATURAL JOIN d NATURAL JOIN e)) \
               NATURAL JOIN (f NATURAL JOIN (g NATURAL JOIN h))";
    assert_eq!(
        only(&verified_only_select(sql).from).joins,
        vec![
            join(nest!(table("b"), nest!(table("c"), table("d"), table("e")))),
            join(nest!(table("f"), nest!(table("g"), table("h"))))
        ],
    );

    let sql = "SELECT * FROM (a NATURAL JOIN b) NATURAL JOIN c";
    let select = verified_only_select(sql);
    let from = only(select.from);
    assert_eq!(from.relation, nest!(table("a"), table("b")));
    assert_eq!(from.joins, vec![join(table("c"))]);

    let sql = "SELECT * FROM (((a NATURAL JOIN b)))";
    let select = verified_only_select(sql);
    let from = only(select.from);
    assert_eq!(from.relation, nest!(nest!(nest!(table("a"), table("b")))));
    assert_eq!(from.joins, vec![]);

    let sql = "SELECT * FROM a NATURAL JOIN (((b NATURAL JOIN c)))";
    let select = verified_only_select(sql);
    let from = only(select.from);
    assert_eq!(from.relation, table("a"));
    assert_eq!(
        from.joins,
        vec![join(nest!(nest!(nest!(table("b"), table("c")))))]
    );

    let sql = "SELECT * FROM (a NATURAL JOIN b) AS c";
    let select = verified_only_select(sql);
    let from = only(select.from);
    assert_eq!(
        from.relation,
        TableFactor::NestedJoin {
            table_with_joins: Box::new(TableWithJoins {
                relation: table("a"),
                joins: vec![join(table("b"))],
            }),
            alias: table_alias("c")
        }
    );
    assert_eq!(from.joins, vec![]);
}

#[test]
fn parse_join_syntax_variants() {
    one_statement_parses_to(
        "SELECT c1 FROM t1 INNER JOIN t2 USING(c1)",
        "SELECT c1 FROM t1 JOIN t2 USING(c1)",
    );
    one_statement_parses_to(
        "SELECT c1 FROM t1 LEFT OUTER JOIN t2 USING(c1)",
        "SELECT c1 FROM t1 LEFT JOIN t2 USING(c1)",
    );
    one_statement_parses_to(
        "SELECT c1 FROM t1 RIGHT OUTER JOIN t2 USING(c1)",
        "SELECT c1 FROM t1 RIGHT JOIN t2 USING(c1)",
    );
    one_statement_parses_to(
        "SELECT c1 FROM t1 FULL OUTER JOIN t2 USING(c1)",
        "SELECT c1 FROM t1 FULL JOIN t2 USING(c1)",
    );

    let res = parse_sql_statements("SELECT * FROM a OUTER JOIN b ON 1");
    assert_eq!(
        ParserError::ParserError("Expected APPLY, found: JOIN".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_ctes() {
    let cte_sqls = vec!["SELECT 1 AS foo", "SELECT 2 AS bar"];
    let with = &format!(
        "WITH a AS ({}), b AS ({}) SELECT foo + bar FROM a, b",
        cte_sqls[0], cte_sqls[1]
    );

    fn assert_ctes_in_select(expected: &[&str], sel: &Query) {
        for (i, exp) in expected.iter().enumerate() {
            let Cte { alias, query, .. } = &sel.with.as_ref().unwrap().cte_tables[i];
            assert_eq!(*exp, query.to_string());
            assert_eq!(
                if i == 0 {
                    Ident::new("a")
                } else {
                    Ident::new("b")
                },
                alias.name
            );
            assert!(alias.columns.is_empty());
        }
    }

    // Top-level CTE
    assert_ctes_in_select(&cte_sqls, &verified_query(with));
    // CTE in a subquery
    let sql = &format!("SELECT ({})", with);
    let select = verified_only_select(sql);
    match expr_from_projection(only(&select.projection)) {
        Expr::Subquery(ref subquery) => {
            assert_ctes_in_select(&cte_sqls, subquery.as_ref());
        }
        _ => panic!("Expected subquery"),
    }
    // CTE in a derived table
    let sql = &format!("SELECT * FROM ({})", with);
    let select = verified_only_select(sql);
    match only(select.from).relation {
        TableFactor::Derived { subquery, .. } => {
            assert_ctes_in_select(&cte_sqls, subquery.as_ref())
        }
        _ => panic!("Expected derived table"),
    }
    // CTE in a view
    let sql = &format!("CREATE VIEW v AS {}", with);
    match verified_stmt(sql) {
        Statement::CreateView { query, .. } => assert_ctes_in_select(&cte_sqls, &query),
        _ => panic!("Expected CREATE VIEW"),
    }
    // CTE in a CTE...
    let sql = &format!("WITH outer_cte AS ({}) SELECT * FROM outer_cte", with);
    let select = verified_query(sql);
    assert_ctes_in_select(&cte_sqls, &only(&select.with.unwrap().cte_tables).query);
}

#[test]
fn parse_cte_renamed_columns() {
    let sql = "WITH cte (col1, col2) AS (SELECT foo, bar FROM baz) SELECT * FROM cte";
    let query = all_dialects().verified_query(sql);
    assert_eq!(
        vec![Ident::new("col1"), Ident::new("col2")],
        query
            .with
            .unwrap()
            .cte_tables
            .first()
            .unwrap()
            .alias
            .columns
    );
}

#[test]
fn parse_recursive_cte() {
    let cte_query = "SELECT 1 UNION ALL SELECT val + 1 FROM nums WHERE val < 10".to_owned();
    let sql = &format!(
        "WITH RECURSIVE nums (val) AS ({}) SELECT * FROM nums",
        cte_query
    );

    let cte_query = verified_query(&cte_query);
    let query = verified_query(sql);

    let with = query.with.as_ref().unwrap();
    assert!(with.recursive);
    assert_eq!(with.cte_tables.len(), 1);
    let expected = Cte {
        alias: TableAlias {
            name: Ident {
                value: "nums".to_string(),
                quote_style: None,
            },
            columns: vec![Ident {
                value: "val".to_string(),
                quote_style: None,
            }],
        },
        query: cte_query,
        from: None,
    };
    assert_eq!(with.cte_tables.first().unwrap(), &expected);
}

#[test]
fn parse_derived_tables() {
    let sql = "SELECT a.x, b.y FROM (SELECT x FROM foo) AS a CROSS JOIN (SELECT y FROM bar) AS b";
    let _ = verified_only_select(sql);
    //TODO: add assertions

    let sql = "SELECT a.x, b.y \
               FROM (SELECT x FROM foo) AS a (x) \
               CROSS JOIN (SELECT y FROM bar) AS b (y)";
    let _ = verified_only_select(sql);
    //TODO: add assertions

    let sql = "SELECT * FROM (((SELECT 1)))";
    let _ = verified_only_select(sql);
    // TODO: add assertions

    let sql = "SELECT * FROM t NATURAL JOIN (((SELECT 1)))";
    let _ = verified_only_select(sql);
    // TODO: add assertions

    let sql = "SELECT * FROM (((SELECT 1) UNION (SELECT 2)) AS t1 NATURAL JOIN t2)";
    let select = verified_only_select(sql);
    let from = only(select.from);
    assert_eq!(
        from.relation,
        TableFactor::NestedJoin {
            table_with_joins: Box::new(TableWithJoins {
                relation: TableFactor::Derived {
                    lateral: false,
                    subquery: Box::new(verified_query("(SELECT 1) UNION (SELECT 2)")),
                    alias: Some(TableAlias {
                        name: "t1".into(),
                        columns: vec![],
                    })
                },
                joins: vec![Join {
                    relation: TableFactor::Table {
                        name: ObjectName(vec!["t2".into()]),
                        alias: None,
                        args: None,
                        with_hints: vec![],
                    },
                    join_operator: JoinOperator::Inner(JoinConstraint::Natural),
                }],
            }),
            alias: None
        }
    );
}

#[test]
fn parse_union() {
    // TODO: add assertions
    verified_stmt("SELECT 1 UNION SELECT 2");
    verified_stmt("SELECT 1 UNION ALL SELECT 2");
    verified_stmt("SELECT 1 EXCEPT SELECT 2");
    verified_stmt("SELECT 1 EXCEPT ALL SELECT 2");
    verified_stmt("SELECT 1 INTERSECT SELECT 2");
    verified_stmt("SELECT 1 INTERSECT ALL SELECT 2");
    verified_stmt("SELECT 1 UNION SELECT 2 UNION SELECT 3");
    verified_stmt("SELECT 1 EXCEPT SELECT 2 UNION SELECT 3"); // Union[Except[1,2], 3]
    verified_stmt("SELECT 1 INTERSECT (SELECT 2 EXCEPT SELECT 3)");
    verified_stmt("WITH cte AS (SELECT 1 AS foo) (SELECT foo FROM cte ORDER BY 1 LIMIT 1)");
    verified_stmt("SELECT 1 UNION (SELECT 2 ORDER BY 1 LIMIT 1)");
    verified_stmt("SELECT 1 UNION SELECT 2 INTERSECT SELECT 3"); // Union[1, Intersect[2,3]]
    verified_stmt("SELECT foo FROM tab UNION SELECT bar FROM TAB");
    verified_stmt("(SELECT * FROM new EXCEPT SELECT * FROM old) UNION ALL (SELECT * FROM old EXCEPT SELECT * FROM new) ORDER BY 1");
}

#[test]
fn parse_values() {
    verified_stmt("SELECT * FROM (VALUES (1), (2), (3))");
    verified_stmt("SELECT * FROM (VALUES (1), (2), (3)), (VALUES (1, 2, 3))");
    verified_stmt("SELECT * FROM (VALUES (1)) UNION VALUES (1)");
}

#[test]
fn parse_multiple_statements() {
    fn test_with(sql1: &str, sql2_kw: &str, sql2_rest: &str) {
        // Check that a string consisting of two statements delimited by a semicolon
        // parses the same as both statements individually:
        let res = parse_sql_statements(&(sql1.to_owned() + ";" + sql2_kw + sql2_rest));
        assert_eq!(
            vec![
                one_statement_parses_to(sql1, ""),
                one_statement_parses_to(&(sql2_kw.to_owned() + sql2_rest), ""),
            ],
            res.unwrap()
        );
        // Check that extra semicolon at the end is stripped by normalization:
        one_statement_parses_to(&(sql1.to_owned() + ";"), sql1);
        // Check that forgetting the semicolon results in an error:
        let res = parse_sql_statements(&(sql1.to_owned() + " " + sql2_kw + sql2_rest));
        assert_eq!(
            ParserError::ParserError("Expected end of statement, found: ".to_string() + sql2_kw),
            res.unwrap_err()
        );
    }
    test_with("SELECT foo", "SELECT", " bar");
    // ensure that SELECT/WITH is not parsed as a table or column alias if ';'
    // separating the statements is omitted:
    test_with("SELECT foo FROM baz", "SELECT", " bar");
    test_with("SELECT foo", "WITH", " cte AS (SELECT 1 AS s) SELECT bar");
    test_with(
        "SELECT foo FROM baz",
        "WITH",
        " cte AS (SELECT 1 AS s) SELECT bar",
    );
    test_with("DELETE FROM foo", "SELECT", " bar");
    test_with("INSERT INTO foo VALUES (1)", "SELECT", " bar");
    test_with("CREATE TABLE foo (baz INT)", "SELECT", " bar");
    // Make sure that empty statements do not cause an error:
    let res = parse_sql_statements(";;");
    assert_eq!(0, res.unwrap().len());
}

#[test]
fn parse_scalar_subqueries() {
    let sql = "(SELECT 1) + (SELECT 2)";
    assert_matches!(
        verified_expr(sql),
        Expr::BinaryOp {
            op: BinaryOperator::Plus,
            ..
        }
    );
}

#[test]
fn parse_substring() {
    one_statement_parses_to("SELECT SUBSTRING('1')", "SELECT SUBSTRING('1')");

    one_statement_parses_to(
        "SELECT SUBSTRING('1' FROM 1)",
        "SELECT SUBSTRING('1' FROM 1)",
    );

    one_statement_parses_to(
        "SELECT SUBSTRING('1' FROM 1 FOR 3)",
        "SELECT SUBSTRING('1' FROM 1 FOR 3)",
    );

    one_statement_parses_to("SELECT SUBSTRING('1' FOR 3)", "SELECT SUBSTRING('1' FOR 3)");
}

#[test]
fn parse_overlay() {
    one_statement_parses_to(
        "SELECT OVERLAY('abccccde' PLACING 'abc' FROM 3)",
        "SELECT OVERLAY('abccccde' PLACING 'abc' FROM 3)",
    );
    one_statement_parses_to(
        "SELECT OVERLAY('abccccde' PLACING 'abc' FROM 3 FOR 12)",
        "SELECT OVERLAY('abccccde' PLACING 'abc' FROM 3 FOR 12)",
    );
    assert_eq!(
        ParserError::ParserError("Expected PLACING, found: FROM".to_owned()),
        parse_sql_statements("SELECT OVERLAY('abccccde' FROM 3)").unwrap_err(),
    );

    let sql = "SELECT OVERLAY('abcdef' PLACING name FROM 3 FOR id + 1) FROM CUSTOMERS";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Overlay {
            expr: Box::new(Expr::Value(Value::SingleQuotedString("abcdef".to_string()))),
            overlay_what: Box::new(Expr::Identifier(Ident::new("name"))),
            overlay_from: Box::new(Expr::Value(number("3"))),
            overlay_for: Some(Box::new(Expr::BinaryOp {
                left: Box::new(Expr::Identifier(Ident::new("id"))),
                op: BinaryOperator::Plus,
                right: Box::new(Expr::Value(number("1"))),
            }))
        },
        expr_from_projection(only(&select.projection))
    );
}

#[test]
fn parse_trim() {
    one_statement_parses_to(
        "SELECT TRIM(BOTH 'xyz' FROM 'xyzfooxyz')",
        "SELECT TRIM(BOTH 'xyz' FROM 'xyzfooxyz')",
    );

    one_statement_parses_to(
        "SELECT TRIM(LEADING 'xyz' FROM 'xyzfooxyz')",
        "SELECT TRIM(LEADING 'xyz' FROM 'xyzfooxyz')",
    );

    one_statement_parses_to(
        "SELECT TRIM(TRAILING 'xyz' FROM 'xyzfooxyz')",
        "SELECT TRIM(TRAILING 'xyz' FROM 'xyzfooxyz')",
    );

    one_statement_parses_to(
        "SELECT TRIM('xyz' FROM 'xyzfooxyz')",
        "SELECT TRIM('xyz' FROM 'xyzfooxyz')",
    );
    one_statement_parses_to("SELECT TRIM('   foo   ')", "SELECT TRIM('   foo   ')");
    one_statement_parses_to(
        "SELECT TRIM(LEADING '   foo   ')",
        "SELECT TRIM(LEADING '   foo   ')",
    );

    assert_eq!(
        ParserError::ParserError("Expected ), found: 'xyz'".to_owned()),
        parse_sql_statements("SELECT TRIM(FOO 'xyz' FROM 'xyzfooxyz')").unwrap_err()
    );
}

#[test]
fn parse_exists_subquery() {
    let expected_inner = verified_query("SELECT 1");
    let sql = "SELECT * FROM t WHERE EXISTS (SELECT 1)";
    let select = verified_only_select(sql);
    assert_eq!(
        Expr::Exists {
            negated: false,
            subquery: Box::new(expected_inner.clone())
        },
        select.selection.unwrap(),
    );

    let sql = "SELECT * FROM t WHERE NOT EXISTS (SELECT 1)";
    let select = verified_only_select(sql);
    assert_eq!(
        Expr::Exists {
            negated: true,
            subquery: Box::new(expected_inner)
        },
        select.selection.unwrap(),
    );

    verified_stmt("SELECT * FROM t WHERE EXISTS (WITH u AS (SELECT 1) SELECT * FROM u)");
    verified_stmt("SELECT EXISTS (SELECT 1)");

    let res = parse_sql_statements("SELECT EXISTS (");
    assert_eq!(
        ParserError::ParserError(
            "Expected SELECT, VALUES, or a subquery in the query body, found: EOF".to_string()
        ),
        res.unwrap_err(),
    );

    let res = parse_sql_statements("SELECT EXISTS (NULL)");
    assert_eq!(
        ParserError::ParserError(
            "Expected SELECT, VALUES, or a subquery in the query body, found: NULL".to_string()
        ),
        res.unwrap_err(),
    );
}

#[test]
fn parse_create_database() {
    let sql = "CREATE DATABASE mydb";
    match verified_stmt(sql) {
        Statement::CreateDatabase {
            db_name,
            if_not_exists,
            location,
            managed_location,
        } => {
            assert_eq!("mydb", db_name.to_string());
            assert!(!if_not_exists);
            assert_eq!(None, location);
            assert_eq!(None, managed_location);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_database_ine() {
    let sql = "CREATE DATABASE IF NOT EXISTS mydb";
    match verified_stmt(sql) {
        Statement::CreateDatabase {
            db_name,
            if_not_exists,
            location,
            managed_location,
        } => {
            assert_eq!("mydb", db_name.to_string());
            assert!(if_not_exists);
            assert_eq!(None, location);
            assert_eq!(None, managed_location);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_view() {
    let sql = "CREATE VIEW myschema.myview AS SELECT foo FROM bar";
    match verified_stmt(sql) {
        Statement::CreateView {
            name,
            columns,
            query,
            or_replace,
            materialized,
            with_options,
        } => {
            assert_eq!("myschema.myview", name.to_string());
            assert_eq!(Vec::<Ident>::new(), columns);
            assert_eq!("SELECT foo FROM bar", query.to_string());
            assert!(!materialized);
            assert!(!or_replace);
            assert_eq!(with_options, vec![]);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_view_with_options() {
    let sql = "CREATE VIEW v WITH (foo = 'bar', a = 123) AS SELECT 1";
    match verified_stmt(sql) {
        Statement::CreateView { with_options, .. } => {
            assert_eq!(
                vec![
                    SqlOption {
                        name: "foo".into(),
                        value: Value::SingleQuotedString("bar".into())
                    },
                    SqlOption {
                        name: "a".into(),
                        value: number("123")
                    },
                ],
                with_options
            );
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_view_with_columns() {
    let sql = "CREATE VIEW v (has, cols) AS SELECT 1, 2";
    match verified_stmt(sql) {
        Statement::CreateView {
            name,
            columns,
            or_replace,
            with_options,
            query,
            materialized,
        } => {
            assert_eq!("v", name.to_string());
            assert_eq!(columns, vec![Ident::new("has"), Ident::new("cols")]);
            assert_eq!(with_options, vec![]);
            assert_eq!("SELECT 1, 2", query.to_string());
            assert!(!materialized);
            assert!(!or_replace)
        }
        _ => unreachable!(),
    }
}
#[test]
fn parse_create_or_replace_view() {
    let sql = "CREATE OR REPLACE VIEW v AS SELECT 1";
    match verified_stmt(sql) {
        Statement::CreateView {
            name,
            columns,
            or_replace,
            with_options,
            query,
            materialized,
        } => {
            assert_eq!("v", name.to_string());
            assert_eq!(columns, vec![]);
            assert_eq!(with_options, vec![]);
            assert_eq!("SELECT 1", query.to_string());
            assert!(!materialized);
            assert!(or_replace)
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_or_replace_materialized_view() {
    // Supported in BigQuery (Beta)
    // https://cloud.google.com/bigquery/docs/materialized-views-intro
    // and Snowflake:
    // https://docs.snowflake.com/en/sql-reference/sql/create-materialized-view.html
    let sql = "CREATE OR REPLACE MATERIALIZED VIEW v AS SELECT 1";
    match verified_stmt(sql) {
        Statement::CreateView {
            name,
            columns,
            or_replace,
            with_options,
            query,
            materialized,
        } => {
            assert_eq!("v", name.to_string());
            assert_eq!(columns, vec![]);
            assert_eq!(with_options, vec![]);
            assert_eq!("SELECT 1", query.to_string());
            assert!(materialized);
            assert!(or_replace)
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_create_materialized_view() {
    let sql = "CREATE MATERIALIZED VIEW myschema.myview AS SELECT foo FROM bar";
    match verified_stmt(sql) {
        Statement::CreateView {
            name,
            or_replace,
            columns,
            query,
            materialized,
            with_options,
        } => {
            assert_eq!("myschema.myview", name.to_string());
            assert_eq!(Vec::<Ident>::new(), columns);
            assert_eq!("SELECT foo FROM bar", query.to_string());
            assert!(materialized);
            assert_eq!(with_options, vec![]);
            assert!(!or_replace);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_drop_table() {
    let sql = "DROP TABLE foo";
    match verified_stmt(sql) {
        Statement::Drop {
            object_type,
            if_exists,
            names,
            cascade,
            purge: _,
        } => {
            assert!(!if_exists);
            assert_eq!(ObjectType::Table, object_type);
            assert_eq!(
                vec!["foo"],
                names.iter().map(ToString::to_string).collect::<Vec<_>>()
            );
            assert!(!cascade);
        }
        _ => unreachable!(),
    }

    let sql = "DROP TABLE IF EXISTS foo, bar CASCADE";
    match verified_stmt(sql) {
        Statement::Drop {
            object_type,
            if_exists,
            names,
            cascade,
            purge: _,
        } => {
            assert!(if_exists);
            assert_eq!(ObjectType::Table, object_type);
            assert_eq!(
                vec!["foo", "bar"],
                names.iter().map(ToString::to_string).collect::<Vec<_>>()
            );
            assert!(cascade);
        }
        _ => unreachable!(),
    }

    let sql = "DROP TABLE";
    assert_eq!(
        ParserError::ParserError("Expected identifier, found: EOF".to_string()),
        parse_sql_statements(sql).unwrap_err(),
    );

    let sql = "DROP TABLE IF EXISTS foo, bar CASCADE RESTRICT";
    assert_eq!(
        ParserError::ParserError("Cannot specify both CASCADE and RESTRICT in DROP".to_string()),
        parse_sql_statements(sql).unwrap_err(),
    );
}

#[test]
fn parse_drop_view() {
    let sql = "DROP VIEW myschema.myview";
    match verified_stmt(sql) {
        Statement::Drop {
            names, object_type, ..
        } => {
            assert_eq!(
                vec!["myschema.myview"],
                names.iter().map(ToString::to_string).collect::<Vec<_>>()
            );
            assert_eq!(ObjectType::View, object_type);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_invalid_subquery_without_parens() {
    let res = parse_sql_statements("SELECT SELECT 1 FROM bar WHERE 1=1 FROM baz");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: 1".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_offset() {
    let expect = Some(Offset {
        value: Expr::Value(number("2")),
        rows: OffsetRows::Rows,
    });
    let ast = verified_query("SELECT foo FROM bar OFFSET 2 ROWS");
    assert_eq!(ast.offset, expect);
    let ast = verified_query("SELECT foo FROM bar WHERE foo = 4 OFFSET 2 ROWS");
    assert_eq!(ast.offset, expect);
    let ast = verified_query("SELECT foo FROM bar ORDER BY baz OFFSET 2 ROWS");
    assert_eq!(ast.offset, expect);
    let ast = verified_query("SELECT foo FROM bar WHERE foo = 4 ORDER BY baz OFFSET 2 ROWS");
    assert_eq!(ast.offset, expect);
    let ast = verified_query("SELECT foo FROM (SELECT * FROM bar OFFSET 2 ROWS) OFFSET 2 ROWS");
    assert_eq!(ast.offset, expect);
    match *ast.body {
        SetExpr::Select(s) => match only(s.from).relation {
            TableFactor::Derived { subquery, .. } => {
                assert_eq!(subquery.offset, expect);
            }
            _ => panic!("Test broke"),
        },
        _ => panic!("Test broke"),
    }
    let ast = verified_query("SELECT 'foo' OFFSET 0 ROWS");
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::Value(number("0")),
            rows: OffsetRows::Rows,
        })
    );
    let ast = verified_query("SELECT 'foo' OFFSET 1 ROW");
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::Value(number("1")),
            rows: OffsetRows::Row,
        })
    );
    let ast = verified_query("SELECT 'foo' OFFSET 1");
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::Value(number("1")),
            rows: OffsetRows::None,
        })
    );
}

#[test]
fn parse_fetch() {
    let fetch_first_two_rows_only = Some(Fetch {
        with_ties: false,
        percent: false,
        quantity: Some(Expr::Value(number("2"))),
    });
    let ast = verified_query("SELECT foo FROM bar FETCH FIRST 2 ROWS ONLY");
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    let ast = verified_query("SELECT 'foo' FETCH FIRST 2 ROWS ONLY");
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    let ast = verified_query("SELECT foo FROM bar FETCH FIRST ROWS ONLY");
    assert_eq!(
        ast.fetch,
        Some(Fetch {
            with_ties: false,
            percent: false,
            quantity: None,
        })
    );
    let ast = verified_query("SELECT foo FROM bar WHERE foo = 4 FETCH FIRST 2 ROWS ONLY");
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    let ast = verified_query("SELECT foo FROM bar ORDER BY baz FETCH FIRST 2 ROWS ONLY");
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    let ast = verified_query(
        "SELECT foo FROM bar WHERE foo = 4 ORDER BY baz FETCH FIRST 2 ROWS WITH TIES",
    );
    assert_eq!(
        ast.fetch,
        Some(Fetch {
            with_ties: true,
            percent: false,
            quantity: Some(Expr::Value(number("2"))),
        })
    );
    let ast = verified_query("SELECT foo FROM bar FETCH FIRST 50 PERCENT ROWS ONLY");
    assert_eq!(
        ast.fetch,
        Some(Fetch {
            with_ties: false,
            percent: true,
            quantity: Some(Expr::Value(number("50"))),
        })
    );
    let ast = verified_query(
        "SELECT foo FROM bar WHERE foo = 4 ORDER BY baz OFFSET 2 ROWS FETCH FIRST 2 ROWS ONLY",
    );
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::Value(number("2")),
            rows: OffsetRows::Rows,
        })
    );
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    let ast = verified_query(
        "SELECT foo FROM (SELECT * FROM bar FETCH FIRST 2 ROWS ONLY) FETCH FIRST 2 ROWS ONLY",
    );
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    match *ast.body {
        SetExpr::Select(s) => match only(s.from).relation {
            TableFactor::Derived { subquery, .. } => {
                assert_eq!(subquery.fetch, fetch_first_two_rows_only);
            }
            _ => panic!("Test broke"),
        },
        _ => panic!("Test broke"),
    }
    let ast = verified_query("SELECT foo FROM (SELECT * FROM bar OFFSET 2 ROWS FETCH FIRST 2 ROWS ONLY) OFFSET 2 ROWS FETCH FIRST 2 ROWS ONLY");
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::Value(number("2")),
            rows: OffsetRows::Rows,
        })
    );
    assert_eq!(ast.fetch, fetch_first_two_rows_only);
    match *ast.body {
        SetExpr::Select(s) => match only(s.from).relation {
            TableFactor::Derived { subquery, .. } => {
                assert_eq!(
                    subquery.offset,
                    Some(Offset {
                        value: Expr::Value(number("2")),
                        rows: OffsetRows::Rows,
                    })
                );
                assert_eq!(subquery.fetch, fetch_first_two_rows_only);
            }
            _ => panic!("Test broke"),
        },
        _ => panic!("Test broke"),
    }
}

#[test]
fn parse_fetch_variations() {
    one_statement_parses_to(
        "SELECT foo FROM bar FETCH FIRST 10 ROW ONLY",
        "SELECT foo FROM bar FETCH FIRST 10 ROWS ONLY",
    );
    one_statement_parses_to(
        "SELECT foo FROM bar FETCH NEXT 10 ROW ONLY",
        "SELECT foo FROM bar FETCH FIRST 10 ROWS ONLY",
    );
    one_statement_parses_to(
        "SELECT foo FROM bar FETCH NEXT 10 ROWS WITH TIES",
        "SELECT foo FROM bar FETCH FIRST 10 ROWS WITH TIES",
    );
    one_statement_parses_to(
        "SELECT foo FROM bar FETCH NEXT ROWS WITH TIES",
        "SELECT foo FROM bar FETCH FIRST ROWS WITH TIES",
    );
    one_statement_parses_to(
        "SELECT foo FROM bar FETCH FIRST ROWS ONLY",
        "SELECT foo FROM bar FETCH FIRST ROWS ONLY",
    );
}

#[test]
fn lateral_derived() {
    fn chk(lateral_in: bool) {
        let lateral_str = if lateral_in { "LATERAL " } else { "" };
        let sql = format!(
            "SELECT * FROM customer LEFT JOIN {}\
             (SELECT * FROM order WHERE order.customer = customer.id LIMIT 3) AS order ON true",
            lateral_str
        );
        let select = verified_only_select(&sql);
        let from = only(select.from);
        assert_eq!(from.joins.len(), 1);
        let join = &from.joins[0];
        assert_eq!(
            join.join_operator,
            JoinOperator::LeftOuter(JoinConstraint::On(Expr::Value(Value::Boolean(true))))
        );
        if let TableFactor::Derived {
            lateral,
            ref subquery,
            alias: Some(ref alias),
        } = join.relation
        {
            assert_eq!(lateral_in, lateral);
            assert_eq!(Ident::new("order"), alias.name);
            assert_eq!(
                subquery.to_string(),
                "SELECT * FROM order WHERE order.customer = customer.id LIMIT 3"
            );
        } else {
            unreachable!()
        }
    }
    chk(false);
    chk(true);

    let sql = "SELECT * FROM customer LEFT JOIN LATERAL generate_series(1, customer.id)";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError(
            "Expected subquery after LATERAL, found: generate_series".to_string()
        ),
        res.unwrap_err()
    );

    let sql = "SELECT * FROM a LEFT JOIN LATERAL (b CROSS JOIN c)";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError(
            "Expected SELECT, VALUES, or a subquery in the query body, found: b".to_string()
        ),
        res.unwrap_err()
    );
}

#[test]
fn parse_start_transaction() {
    match verified_stmt("START TRANSACTION READ ONLY, READ WRITE, ISOLATION LEVEL SERIALIZABLE") {
        Statement::StartTransaction { modes } => assert_eq!(
            modes,
            vec![
                TransactionMode::AccessMode(TransactionAccessMode::ReadOnly),
                TransactionMode::AccessMode(TransactionAccessMode::ReadWrite),
                TransactionMode::IsolationLevel(TransactionIsolationLevel::Serializable),
            ]
        ),
        _ => unreachable!(),
    }

    // For historical reasons, PostgreSQL allows the commas between the modes to
    // be omitted.
    match one_statement_parses_to(
        "START TRANSACTION READ ONLY READ WRITE ISOLATION LEVEL SERIALIZABLE",
        "START TRANSACTION READ ONLY, READ WRITE, ISOLATION LEVEL SERIALIZABLE",
    ) {
        Statement::StartTransaction { modes } => assert_eq!(
            modes,
            vec![
                TransactionMode::AccessMode(TransactionAccessMode::ReadOnly),
                TransactionMode::AccessMode(TransactionAccessMode::ReadWrite),
                TransactionMode::IsolationLevel(TransactionIsolationLevel::Serializable),
            ]
        ),
        _ => unreachable!(),
    }

    verified_stmt("START TRANSACTION");
    one_statement_parses_to("BEGIN", "START TRANSACTION");
    one_statement_parses_to("BEGIN WORK", "START TRANSACTION");
    one_statement_parses_to("BEGIN TRANSACTION", "START TRANSACTION");

    verified_stmt("START TRANSACTION ISOLATION LEVEL READ UNCOMMITTED");
    verified_stmt("START TRANSACTION ISOLATION LEVEL READ COMMITTED");
    verified_stmt("START TRANSACTION ISOLATION LEVEL REPEATABLE READ");
    verified_stmt("START TRANSACTION ISOLATION LEVEL SERIALIZABLE");

    // Regression test for https://github.com/sqlparser-rs/sqlparser-rs/pull/139,
    // in which START TRANSACTION would fail to parse if followed by a statement
    // terminator.
    assert_eq!(
        parse_sql_statements("START TRANSACTION; SELECT 1"),
        Ok(vec![
            verified_stmt("START TRANSACTION"),
            verified_stmt("SELECT 1"),
        ])
    );

    let res = parse_sql_statements("START TRANSACTION ISOLATION LEVEL BAD");
    assert_eq!(
        ParserError::ParserError("Expected isolation level, found: BAD".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("START TRANSACTION BAD");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: BAD".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("START TRANSACTION READ ONLY,");
    assert_eq!(
        ParserError::ParserError("Expected transaction mode, found: EOF".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_set_transaction() {
    // SET TRANSACTION shares transaction mode parsing code with START
    // TRANSACTION, so no need to duplicate the tests here. We just do a quick
    // sanity check.
    match verified_stmt("SET TRANSACTION READ ONLY, READ WRITE, ISOLATION LEVEL SERIALIZABLE") {
        Statement::SetTransaction {
            modes,
            session,
            snapshot,
        } => {
            assert_eq!(
                modes,
                vec![
                    TransactionMode::AccessMode(TransactionAccessMode::ReadOnly),
                    TransactionMode::AccessMode(TransactionAccessMode::ReadWrite),
                    TransactionMode::IsolationLevel(TransactionIsolationLevel::Serializable),
                ]
            );
            assert!(!session);
            assert_eq!(snapshot, None);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_commit() {
    match verified_stmt("COMMIT") {
        Statement::Commit { chain: false } => (),
        _ => unreachable!(),
    }

    match verified_stmt("COMMIT AND CHAIN") {
        Statement::Commit { chain: true } => (),
        _ => unreachable!(),
    }

    one_statement_parses_to("COMMIT AND NO CHAIN", "COMMIT");
    one_statement_parses_to("COMMIT WORK AND NO CHAIN", "COMMIT");
    one_statement_parses_to("COMMIT TRANSACTION AND NO CHAIN", "COMMIT");
    one_statement_parses_to("COMMIT WORK AND CHAIN", "COMMIT AND CHAIN");
    one_statement_parses_to("COMMIT TRANSACTION AND CHAIN", "COMMIT AND CHAIN");
    one_statement_parses_to("COMMIT WORK", "COMMIT");
    one_statement_parses_to("COMMIT TRANSACTION", "COMMIT");
}

#[test]
fn parse_rollback() {
    match verified_stmt("ROLLBACK") {
        Statement::Rollback { chain: false } => (),
        _ => unreachable!(),
    }

    match verified_stmt("ROLLBACK AND CHAIN") {
        Statement::Rollback { chain: true } => (),
        _ => unreachable!(),
    }

    one_statement_parses_to("ROLLBACK AND NO CHAIN", "ROLLBACK");
    one_statement_parses_to("ROLLBACK WORK AND NO CHAIN", "ROLLBACK");
    one_statement_parses_to("ROLLBACK TRANSACTION AND NO CHAIN", "ROLLBACK");
    one_statement_parses_to("ROLLBACK WORK AND CHAIN", "ROLLBACK AND CHAIN");
    one_statement_parses_to("ROLLBACK TRANSACTION AND CHAIN", "ROLLBACK AND CHAIN");
    one_statement_parses_to("ROLLBACK WORK", "ROLLBACK");
    one_statement_parses_to("ROLLBACK TRANSACTION", "ROLLBACK");
}

#[test]
#[should_panic(expected = "Parse results with GenericDialect are different from PostgreSqlDialect")]
fn ensure_multiple_dialects_are_tested() {
    // The SQL here must be parsed differently by different dialects.
    // At the time of writing, `@foo` is accepted as a valid identifier
    // by the Generic and the MSSQL dialect, but not by Postgres and ANSI.
    let _ = parse_sql_statements("SELECT @foo");
}

#[test]
fn parse_create_index() {
    let sql = "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test(name,age DESC)";
    let indexed_columns = vec![
        OrderByExpr {
            expr: Expr::Identifier(Ident::new("name")),
            asc: None,
            nulls_first: None,
        },
        OrderByExpr {
            expr: Expr::Identifier(Ident::new("age")),
            asc: Some(false),
            nulls_first: None,
        },
    ];
    match verified_stmt(sql) {
        Statement::CreateIndex {
            name,
            table_name,
            columns,
            unique,
            if_not_exists,
        } => {
            assert_eq!("idx_name", name.to_string());
            assert_eq!("test", table_name.to_string());
            assert_eq!(indexed_columns, columns);
            assert!(unique);
            assert!(if_not_exists)
        }
        _ => unreachable!(),
    }
}
#[test]
fn parse_drop_index() {
    let sql = "DROP INDEX idx_a";
    match verified_stmt(sql) {
        Statement::Drop {
            names, object_type, ..
        } => {
            assert_eq!(
                vec!["idx_a"],
                names.iter().map(ToString::to_string).collect::<Vec<_>>()
            );
            assert_eq!(ObjectType::Index, object_type);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_grant() {
    let sql = "GRANT SELECT, INSERT, UPDATE (shape, size), USAGE, DELETE, TRUNCATE, REFERENCES, TRIGGER, CONNECT, CREATE, EXECUTE, TEMPORARY ON abc, def TO xyz, m WITH GRANT OPTION GRANTED BY jj";
    match verified_stmt(sql) {
        Statement::Grant {
            privileges,
            objects,
            grantees,
            with_grant_option,
            granted_by,
            ..
        } => match (privileges, objects) {
            (Privileges::Actions(actions), GrantObjects::Tables(objects)) => {
                assert_eq!(
                    vec![
                        Action::Select { columns: None },
                        Action::Insert { columns: None },
                        Action::Update {
                            columns: Some(vec![
                                Ident {
                                    value: "shape".into(),
                                    quote_style: None
                                },
                                Ident {
                                    value: "size".into(),
                                    quote_style: None
                                }
                            ])
                        },
                        Action::Usage,
                        Action::Delete,
                        Action::Truncate,
                        Action::References { columns: None },
                        Action::Trigger,
                        Action::Connect,
                        Action::Create,
                        Action::Execute,
                        Action::Temporary,
                    ],
                    actions
                );
                assert_eq!(
                    vec!["abc", "def"],
                    objects.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
                assert_eq!(
                    vec!["xyz", "m"],
                    grantees.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
                assert!(with_grant_option);
                assert_eq!("jj", granted_by.unwrap().to_string());
            }
            _ => unreachable!(),
        },
        _ => unreachable!(),
    }

    let sql2 = "GRANT INSERT ON ALL TABLES IN SCHEMA public TO browser";
    match verified_stmt(sql2) {
        Statement::Grant {
            privileges,
            objects,
            grantees,
            with_grant_option,
            ..
        } => match (privileges, objects) {
            (Privileges::Actions(actions), GrantObjects::AllTablesInSchema { schemas }) => {
                assert_eq!(vec![Action::Insert { columns: None }], actions);
                assert_eq!(
                    vec!["public"],
                    schemas.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
                assert_eq!(
                    vec!["browser"],
                    grantees.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
                assert!(!with_grant_option);
            }
            _ => unreachable!(),
        },
        _ => unreachable!(),
    }

    let sql3 = "GRANT USAGE, SELECT ON SEQUENCE p TO u";
    match verified_stmt(sql3) {
        Statement::Grant {
            privileges,
            objects,
            grantees,
            granted_by,
            ..
        } => match (privileges, objects, granted_by) {
            (Privileges::Actions(actions), GrantObjects::Sequences(objects), None) => {
                assert_eq!(
                    vec![Action::Usage, Action::Select { columns: None }],
                    actions
                );
                assert_eq!(
                    vec!["p"],
                    objects.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
                assert_eq!(
                    vec!["u"],
                    grantees.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
            }
            _ => unreachable!(),
        },
        _ => unreachable!(),
    }

    let sql4 = "GRANT ALL PRIVILEGES ON aa, b TO z";
    match verified_stmt(sql4) {
        Statement::Grant { privileges, .. } => {
            assert_eq!(
                Privileges::All {
                    with_privileges_keyword: true
                },
                privileges
            );
        }
        _ => unreachable!(),
    }

    let sql5 = "GRANT ALL ON SCHEMA aa, b TO z";
    match verified_stmt(sql5) {
        Statement::Grant {
            privileges,
            objects,
            ..
        } => match (privileges, objects) {
            (
                Privileges::All {
                    with_privileges_keyword,
                },
                GrantObjects::Schemas(schemas),
            ) => {
                assert!(!with_privileges_keyword);
                assert_eq!(
                    vec!["aa", "b"],
                    schemas.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
            }
            _ => unreachable!(),
        },
        _ => unreachable!(),
    }

    let sql6 = "GRANT USAGE ON ALL SEQUENCES IN SCHEMA bus TO a, beta WITH GRANT OPTION";
    match verified_stmt(sql6) {
        Statement::Grant {
            privileges,
            objects,
            ..
        } => match (privileges, objects) {
            (Privileges::Actions(actions), GrantObjects::AllSequencesInSchema { schemas }) => {
                assert_eq!(vec![Action::Usage], actions);
                assert_eq!(
                    vec!["bus"],
                    schemas.iter().map(ToString::to_string).collect::<Vec<_>>()
                );
            }
            _ => unreachable!(),
        },
        _ => unreachable!(),
    }
}

#[test]
fn test_revoke() {
    let sql = "REVOKE ALL PRIVILEGES ON users, auth FROM analyst CASCADE";
    match verified_stmt(sql) {
        Statement::Revoke {
            privileges,
            objects: GrantObjects::Tables(tables),
            grantees,
            cascade,
            granted_by,
        } => {
            assert_eq!(
                Privileges::All {
                    with_privileges_keyword: true
                },
                privileges
            );
            assert_eq!(
                vec!["users", "auth"],
                tables.iter().map(ToString::to_string).collect::<Vec<_>>()
            );
            assert_eq!(
                vec!["analyst"],
                grantees.iter().map(ToString::to_string).collect::<Vec<_>>()
            );
            assert!(cascade);
            assert_eq!(None, granted_by);
        }
        _ => unreachable!(),
    }
}

#[test]
fn parse_merge() {
    let sql = "MERGE INTO s.bar AS dest USING (SELECT * FROM s.foo) AS stg ON dest.D = stg.D AND dest.E = stg.E WHEN NOT MATCHED THEN INSERT (A, B, C) VALUES (stg.A, stg.B, stg.C) WHEN MATCHED AND dest.A = 'a' THEN UPDATE SET dest.F = stg.F, dest.G = stg.G WHEN MATCHED THEN DELETE";
    let sql_no_into = "MERGE s.bar AS dest USING (SELECT * FROM s.foo) AS stg ON dest.D = stg.D AND dest.E = stg.E WHEN NOT MATCHED THEN INSERT (A, B, C) VALUES (stg.A, stg.B, stg.C) WHEN MATCHED AND dest.A = 'a' THEN UPDATE SET dest.F = stg.F, dest.G = stg.G WHEN MATCHED THEN DELETE";
    match (verified_stmt(sql), verified_stmt(sql_no_into)) {
        (
            Statement::Merge {
                into,
                table,
                source,
                on,
                clauses,
            },
            Statement::Merge {
                into: no_into,
                table: table_no_into,
                source: source_no_into,
                on: on_no_into,
                clauses: clauses_no_into,
            },
        ) => {
            assert!(into);
            assert!(!no_into);

            assert_eq!(
                table,
                TableFactor::Table {
                    name: ObjectName(vec![Ident::new("s"), Ident::new("bar")]),
                    alias: Some(TableAlias {
                        name: Ident::new("dest"),
                        columns: vec![]
                    }),
                    args: None,
                    with_hints: vec![]
                }
            );
            assert_eq!(table, table_no_into);

            assert_eq!(
                source,
                TableFactor::Derived {
                    lateral: false,
                    subquery: Box::new(Query {
                        with: None,
                        body: Box::new(SetExpr::Select(Box::new(Select {
                            distinct: false,
                            top: None,
                            projection: vec![SelectItem::Wildcard],
                            into: None,
                            from: vec![TableWithJoins {
                                relation: TableFactor::Table {
                                    name: ObjectName(vec![Ident::new("s"), Ident::new("foo")]),
                                    alias: None,
                                    args: None,
                                    with_hints: vec![]
                                },
                                joins: vec![]
                            }],
                            lateral_views: vec![],
                            selection: None,
                            group_by: vec![],
                            cluster_by: vec![],
                            distribute_by: vec![],
                            sort_by: vec![],
                            having: None,
                            qualify: None,
                        }))),
                        order_by: vec![],
                        limit: None,
                        offset: None,
                        fetch: None,
                        lock: None
                    }),
                    alias: Some(TableAlias {
                        name: Ident {
                            value: "stg".to_string(),
                            quote_style: None
                        },
                        columns: vec![]
                    })
                }
            );
            assert_eq!(source, source_no_into);

            assert_eq!(
                on,
                Box::new(Expr::BinaryOp {
                    left: Box::new(Expr::BinaryOp {
                        left: Box::new(Expr::CompoundIdentifier(vec![
                            Ident::new("dest"),
                            Ident::new("D")
                        ])),
                        op: BinaryOperator::Eq,
                        right: Box::new(Expr::CompoundIdentifier(vec![
                            Ident::new("stg"),
                            Ident::new("D")
                        ]))
                    }),
                    op: BinaryOperator::And,
                    right: Box::new(Expr::BinaryOp {
                        left: Box::new(Expr::CompoundIdentifier(vec![
                            Ident::new("dest"),
                            Ident::new("E")
                        ])),
                        op: BinaryOperator::Eq,
                        right: Box::new(Expr::CompoundIdentifier(vec![
                            Ident::new("stg"),
                            Ident::new("E")
                        ]))
                    })
                })
            );
            assert_eq!(on, on_no_into);

            assert_eq!(
                clauses,
                vec![
                    MergeClause::NotMatched {
                        predicate: None,
                        columns: vec![Ident::new("A"), Ident::new("B"), Ident::new("C")],
                        values: Values(vec![vec![
                            Expr::CompoundIdentifier(vec![Ident::new("stg"), Ident::new("A")]),
                            Expr::CompoundIdentifier(vec![Ident::new("stg"), Ident::new("B")]),
                            Expr::CompoundIdentifier(vec![Ident::new("stg"), Ident::new("C")]),
                        ]])
                    },
                    MergeClause::MatchedUpdate {
                        predicate: Some(Expr::BinaryOp {
                            left: Box::new(Expr::CompoundIdentifier(vec![
                                Ident::new("dest"),
                                Ident::new("A")
                            ])),
                            op: BinaryOperator::Eq,
                            right: Box::new(Expr::Value(Value::SingleQuotedString(
                                "a".to_string()
                            )))
                        }),
                        assignments: vec![
                            Assignment {
                                id: vec![Ident::new("dest"), Ident::new("F")],
                                value: Expr::CompoundIdentifier(vec![
                                    Ident::new("stg"),
                                    Ident::new("F")
                                ])
                            },
                            Assignment {
                                id: vec![Ident::new("dest"), Ident::new("G")],
                                value: Expr::CompoundIdentifier(vec![
                                    Ident::new("stg"),
                                    Ident::new("G")
                                ])
                            }
                        ]
                    },
                    MergeClause::MatchedDelete(None)
                ]
            );
            assert_eq!(clauses, clauses_no_into);
        }
        _ => unreachable!(),
    }
}

#[test]
fn test_merge_into_using_table() {
    let sql = "MERGE INTO target_table USING source_table \
        ON target_table.id = source_table.oooid \
        WHEN MATCHED THEN \
            UPDATE SET target_table.description = source_table.description \
        WHEN NOT MATCHED THEN \
            INSERT (ID, description) VALUES (source_table.id, source_table.description)";

    verified_stmt(sql);
}

#[test]
fn test_merge_with_delimiter() {
    let sql = "MERGE INTO target_table USING source_table \
    ON target_table.id = source_table.oooid \
    WHEN MATCHED THEN \
        UPDATE SET target_table.description = source_table.description \
    WHEN NOT MATCHED THEN \
        INSERT (ID, description) VALUES (source_table.id, source_table.description);";

    match parse_sql_statements(sql) {
        Ok(_) => {}
        _ => unreachable!(),
    }
}

#[test]
fn test_lock() {
    let sql = "SELECT * FROM student WHERE id = '1' FOR UPDATE";
    let ast = verified_query(sql);
    assert_eq!(ast.lock.unwrap(), LockType::Update);

    let sql = "SELECT * FROM student WHERE id = '1' FOR SHARE";
    let ast = verified_query(sql);
    assert_eq!(ast.lock.unwrap(), LockType::Share);
}

#[test]
fn test_placeholder() {
    let sql = "SELECT * FROM student WHERE id = ?";
    let ast = verified_only_select(sql);
    assert_eq!(
        ast.selection,
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("id"))),
            op: BinaryOperator::Eq,
            right: Box::new(Expr::Value(Value::Placeholder("?".into())))
        })
    );

    let dialects = TestedDialects {
        dialects: vec![
            Box::new(GenericDialect {}),
            Box::new(PostgreSqlDialect {}),
            Box::new(MsSqlDialect {}),
            Box::new(AnsiDialect {}),
            Box::new(BigQueryDialect {}),
            Box::new(SnowflakeDialect {}),
            // Note: `$` is the starting word for the HiveDialect identifier
            // Box::new(sqlparser::dialect::HiveDialect {}),
        ],
    };
    let sql = "SELECT * FROM student WHERE id = $Id1";
    let ast = dialects.verified_only_select(sql);
    assert_eq!(
        ast.selection,
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Identifier(Ident::new("id"))),
            op: BinaryOperator::Eq,
            right: Box::new(Expr::Value(Value::Placeholder("$Id1".into())))
        })
    );

    let sql = "SELECT * FROM student LIMIT $1 OFFSET $2";
    let ast = dialects.verified_query(sql);
    assert_eq!(
        ast.limit,
        Some(Expr::Value(Value::Placeholder("$1".into())))
    );
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::Value(Value::Placeholder("$2".into())),
            rows: OffsetRows::None,
        }),
    );

    let sql = "SELECT $fromage_français, :x, ?123";
    let ast = dialects.verified_only_select(sql);
    assert_eq!(
        ast.projection,
        vec![
            UnnamedExpr(Expr::Value(Value::Placeholder("$fromage_français".into()))),
            UnnamedExpr(Expr::Value(Value::Placeholder(":x".into()))),
            UnnamedExpr(Expr::Value(Value::Placeholder("?123".into()))),
        ]
    );
}

#[test]
fn all_keywords_sorted() {
    // assert!(ALL_KEYWORDS.is_sorted())
    let mut copy = Vec::from(ALL_KEYWORDS);
    copy.sort_unstable();
    assert_eq!(copy, ALL_KEYWORDS)
}

fn parse_sql_statements(sql: &str) -> Result<Vec<Statement>, ParserError> {
    all_dialects().parse_sql_statements(sql)
}

fn one_statement_parses_to(sql: &str, canonical: &str) -> Statement {
    all_dialects().one_statement_parses_to(sql, canonical)
}

fn verified_stmt(query: &str) -> Statement {
    all_dialects().verified_stmt(query)
}

fn verified_query(query: &str) -> Query {
    all_dialects().verified_query(query)
}

fn verified_only_select(query: &str) -> Select {
    all_dialects().verified_only_select(query)
}

fn verified_expr(query: &str) -> Expr {
    all_dialects().verified_expr(query)
}

#[test]
fn parse_offset_and_limit() {
    let sql = "SELECT foo FROM bar LIMIT 2 OFFSET 2";
    let expect = Some(Offset {
        value: Expr::Value(number("2")),
        rows: OffsetRows::None,
    });
    let ast = verified_query(sql);
    assert_eq!(ast.offset, expect);
    assert_eq!(ast.limit, Some(Expr::Value(number("2"))));

    // different order is OK
    one_statement_parses_to("SELECT foo FROM bar OFFSET 2 LIMIT 2", sql);

    // expressions are allowed
    let sql = "SELECT foo FROM bar LIMIT 1 + 2 OFFSET 3 * 4";
    let ast = verified_query(sql);
    assert_eq!(
        ast.limit,
        Some(Expr::BinaryOp {
            left: Box::new(Expr::Value(number("1"))),
            op: BinaryOperator::Plus,
            right: Box::new(Expr::Value(number("2"))),
        }),
    );
    assert_eq!(
        ast.offset,
        Some(Offset {
            value: Expr::BinaryOp {
                left: Box::new(Expr::Value(number("3"))),
                op: BinaryOperator::Multiply,
                right: Box::new(Expr::Value(number("4"))),
            },
            rows: OffsetRows::None,
        }),
    );

    // Can't repeat OFFSET / LIMIT
    let res = parse_sql_statements("SELECT foo FROM bar OFFSET 2 OFFSET 2");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: OFFSET".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("SELECT foo FROM bar LIMIT 2 LIMIT 2");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: LIMIT".to_string()),
        res.unwrap_err()
    );

    let res = parse_sql_statements("SELECT foo FROM bar OFFSET 2 LIMIT 2 OFFSET 2");
    assert_eq!(
        ParserError::ParserError("Expected end of statement, found: OFFSET".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_time_functions() {
    let sql = "SELECT CURRENT_TIMESTAMP()";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("CURRENT_TIMESTAMP")]),
            args: vec![],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[0])
    );

    // Validating Parenthesis
    one_statement_parses_to("SELECT CURRENT_TIMESTAMP", sql);

    let sql = "SELECT CURRENT_TIME()";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("CURRENT_TIME")]),
            args: vec![],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[0])
    );

    // Validating Parenthesis
    one_statement_parses_to("SELECT CURRENT_TIME", sql);

    let sql = "SELECT CURRENT_DATE()";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("CURRENT_DATE")]),
            args: vec![],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[0])
    );

    // Validating Parenthesis
    one_statement_parses_to("SELECT CURRENT_DATE", sql);

    let sql = "SELECT LOCALTIME()";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("LOCALTIME")]),
            args: vec![],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[0])
    );

    // Validating Parenthesis
    one_statement_parses_to("SELECT LOCALTIME", sql);

    let sql = "SELECT LOCALTIMESTAMP()";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Function(Function {
            name: ObjectName(vec![Ident::new("LOCALTIMESTAMP")]),
            args: vec![],
            over: None,
            distinct: false,
            special: false,
        }),
        expr_from_projection(&select.projection[0])
    );

    // Validating Parenthesis
    one_statement_parses_to("SELECT LOCALTIMESTAMP", sql);
}

#[test]
fn parse_position() {
    let sql = "SELECT POSITION('@' IN field)";
    let select = verified_only_select(sql);
    assert_eq!(
        &Expr::Position {
            expr: Box::new(Expr::Value(Value::SingleQuotedString("@".to_string()))),
            r#in: Box::new(Expr::Identifier(Ident::new("field"))),
        },
        expr_from_projection(only(&select.projection))
    );
}

#[test]
fn parse_position_negative() {
    let sql = "SELECT POSITION(foo) from bar";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Position function must include IN keyword".to_string()),
        res.unwrap_err()
    );

    let sql = "SELECT POSITION(foo IN) from bar";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError("Expected an expression:, found: )".to_string()),
        res.unwrap_err()
    );
}

#[test]
fn parse_is_boolean() {
    use self::Expr::*;

    let sql = "a IS TRUE";
    assert_eq!(
        IsTrue(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );

    let sql = "a IS NOT TRUE";
    assert_eq!(
        IsNotTrue(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );

    let sql = "a IS FALSE";
    assert_eq!(
        IsFalse(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );

    let sql = "a IS NOT FALSE";
    assert_eq!(
        IsNotFalse(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );

    let sql = "a IS UNKNOWN";
    assert_eq!(
        IsUnknown(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );

    let sql = "a IS NOT UNKNOWN";
    assert_eq!(
        IsNotUnknown(Box::new(Identifier(Ident::new("a")))),
        verified_expr(sql)
    );

    verified_stmt("SELECT f FROM foo WHERE field IS TRUE");
    verified_stmt("SELECT f FROM foo WHERE field IS NOT TRUE");

    verified_stmt("SELECT f FROM foo WHERE field IS FALSE");
    verified_stmt("SELECT f FROM foo WHERE field IS NOT FALSE");

    verified_stmt("SELECT f FROM foo WHERE field IS UNKNOWN");
    verified_stmt("SELECT f FROM foo WHERE field IS NOT UNKNOWN");

    let sql = "SELECT f from foo where field is 0";
    let res = parse_sql_statements(sql);
    assert_eq!(
        ParserError::ParserError(
            "Expected [NOT] NULL or TRUE|FALSE or [NOT] DISTINCT FROM after IS, found: 0"
                .to_string()
        ),
        res.unwrap_err()
    );
}

#[test]
fn parse_discard() {
    let sql = "DISCARD ALL";
    match verified_stmt(sql) {
        Statement::Discard { object_type, .. } => assert_eq!(object_type, DiscardObject::ALL),
        _ => unreachable!(),
    }

    let sql = "DISCARD PLANS";
    match verified_stmt(sql) {
        Statement::Discard { object_type, .. } => assert_eq!(object_type, DiscardObject::PLANS),
        _ => unreachable!(),
    }

    let sql = "DISCARD SEQUENCES";
    match verified_stmt(sql) {
        Statement::Discard { object_type, .. } => assert_eq!(object_type, DiscardObject::SEQUENCES),
        _ => unreachable!(),
    }

    let sql = "DISCARD TEMP";
    match verified_stmt(sql) {
        Statement::Discard { object_type, .. } => assert_eq!(object_type, DiscardObject::TEMP),
        _ => unreachable!(),
    }
}

#[test]
fn parse_cursor() {
    let sql = r#"CLOSE my_cursor"#;
    match verified_stmt(sql) {
        Statement::Close { cursor } => assert_eq!(
            cursor,
            CloseCursor::Specific {
                name: Ident::new("my_cursor"),
            }
        ),
        _ => unreachable!(),
    }

    let sql = r#"CLOSE ALL"#;
    match verified_stmt(sql) {
        Statement::Close { cursor } => assert_eq!(cursor, CloseCursor::All),
        _ => unreachable!(),
    }
}