Fix nullability calculation for CASE expressions (apache#2814)

* Fix nullability calculation for CASE statements * Remove println
cube-js · Aug 15, 2022 · 0e05ba1 · 0e05ba1
1 parent 11c7d76
commit 0e05ba1
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/datafusion/core/src/logical_plan/expr_schema.rs b/datafusion/core/src/logical_plan/expr_schema.rs
@@ -172,7 +172,9 @@ impl ExprSchemable for Expr {
                 } else if let Some(e) = else_expr {
                     e.nullable(input_schema)
                 } else {
-                    Ok(false)
+                    // CASE produces NULL if there is no `else` expr
+                    // (aka when none of the `when_then_exprs` match)
+                    Ok(true)
                 }
             }
             Expr::Cast { expr, .. } => expr.nullable(input_schema),

diff --git a/datafusion/physical-expr/src/expressions/case.rs b/datafusion/physical-expr/src/expressions/case.rs
@@ -406,7 +406,9 @@ impl PhysicalExpr for CaseExpr {
         } else if let Some(e) = &self.else_expr {
             e.nullable(input_schema)
         } else {
-            Ok(false)
+            // CASE produces NULL if there is no `else` expr
+            // (aka when none of the `when_then_exprs` match)
+            Ok(true)
         }
     }