From bb342682da7d863c21e735e77517fd371ebb8fd4 Mon Sep 17 00:00:00 2001
From: Alex Qyoun-ae <4062971+MazterQyou@users.noreply.github.com>
Date: Wed, 10 Aug 2022 03:30:42 +0400
Subject: [PATCH] Support `SHOW COLLATION`

---
 src/ast/mod.rs           | 11 +++++++++++
 src/keywords.rs          |  1 +
 src/parser.rs            |  7 +++++++
 tests/sqlparser_mysql.rs | 28 ++++++++++++++++++++++++++++
 4 files changed, 47 insertions(+)

diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index 5e8296f88..99b93b25c 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -1036,6 +1036,10 @@ pub enum Statement {
         db_name: Option<Ident>,
         filter: Option<ShowStatementFilter>,
     },
+    /// SHOW COLLATION
+    ///
+    /// Note: this is a MySQL-specific statement.
+    ShowCollation { filter: Option<ShowStatementFilter> },
     /// USE
     ///
     /// Note: This is a MySQL-specific statement.
@@ -1892,6 +1896,13 @@ impl fmt::Display for Statement {
                 write!(f, "USE {}", db_name)?;
                 Ok(())
             }
+            Statement::ShowCollation { filter } => {
+                write!(f, "SHOW COLLATION")?;
+                if let Some(filter) = filter {
+                    write!(f, " {}", filter)?;
+                }
+                Ok(())
+            }
             Statement::StartTransaction { modes } => {
                 write!(f, "START TRANSACTION")?;
                 if !modes.is_empty() {
diff --git a/src/keywords.rs b/src/keywords.rs
index 7eb6b420c..a06ddc48d 100644
--- a/src/keywords.rs
+++ b/src/keywords.rs
@@ -131,6 +131,7 @@ define_keywords!(
     CLUSTER,
     COALESCE,
     COLLATE,
+    COLLATION,
     COLLECT,
     COLUMN,
     COLUMNS,
diff --git a/src/parser.rs b/src/parser.rs
index 11f14ecf4..784010efb 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -3758,6 +3758,8 @@ impl<'a> Parser<'a> {
             ))
         } else if self.parse_one_of_keywords(&[Keyword::CREATE]).is_some() {
             Ok(self.parse_show_create()?)
+        } else if self.parse_keyword(Keyword::COLLATION) {
+            Ok(self.parse_show_collation()?)
         } else if self.parse_keyword(Keyword::VARIABLES)
             && dialect_of!(self is MySqlDialect | GenericDialect)
         {
@@ -3841,6 +3843,11 @@ impl<'a> Parser<'a> {
         })
     }
 
+    pub fn parse_show_collation(&mut self) -> Result<Statement, ParserError> {
+        let filter = self.parse_show_statement_filter()?;
+        Ok(Statement::ShowCollation { filter })
+    }
+
     pub fn parse_show_statement_filter(
         &mut self,
     ) -> Result<Option<ShowStatementFilter>, ParserError> {
diff --git a/tests/sqlparser_mysql.rs b/tests/sqlparser_mysql.rs
index 16d0daf8d..c1cfa2876 100644
--- a/tests/sqlparser_mysql.rs
+++ b/tests/sqlparser_mysql.rs
@@ -189,6 +189,12 @@ fn parse_show_extended_full() {
     assert!(mysql_and_generic()
         .parse_sql_statements("SHOW EXTENDED FULL CREATE TABLE mytable")
         .is_err());
+    assert!(mysql_and_generic()
+        .parse_sql_statements("SHOW EXTENDED FULL COLLATION")
+        .is_err());
+    assert!(mysql_and_generic()
+        .parse_sql_statements("SHOW EXTENDED FULL VARIABLES")
+        .is_err());
 }
 
 #[test]
@@ -213,6 +219,28 @@ fn parse_show_create() {
     }
 }
 
+#[test]
+fn parse_show_collation() {
+    assert_eq!(
+        mysql_and_generic().verified_stmt("SHOW COLLATION"),
+        Statement::ShowCollation { filter: None }
+    );
+    assert_eq!(
+        mysql_and_generic().verified_stmt("SHOW COLLATION LIKE 'pattern'"),
+        Statement::ShowCollation {
+            filter: Some(ShowStatementFilter::Like("pattern".into())),
+        }
+    );
+    assert_eq!(
+        mysql_and_generic().verified_stmt("SHOW COLLATION WHERE 1 = 2"),
+        Statement::ShowCollation {
+            filter: Some(ShowStatementFilter::Where(
+                mysql_and_generic().verified_expr("1 = 2")
+            )),
+        }
+    );
+}
+
 #[test]
 fn parse_use() {
     assert_eq!(