fix(optimizer): remove redundant casts (#2945)

tobymao · Feb 9, 2024 · d07ddf9 · d07ddf9
1 parent 76d6634
commit d07ddf9
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Showing 2 changed files with 13 additions and 2 deletions.
diff --git a/sqlglot/optimizer/canonicalize.py b/sqlglot/optimizer/canonicalize.py
@@ -76,9 +76,8 @@ def coerce_type(node: exp.Expression) -> exp.Expression:
 def remove_redundant_casts(expression: exp.Expression) -> exp.Expression:
     if (
         isinstance(expression, exp.Cast)
-        and expression.to.type
         and expression.this.type
-        and expression.to.type.this == expression.this.type.this
+        and expression.to.this == expression.this.type.this
     ):
         return expression.this
     return expression

diff --git a/tests/fixtures/optimizer/canonicalize.sql b/tests/fixtures/optimizer/canonicalize.sql
@@ -96,3 +96,15 @@ DATE_TRUNC('DAY', CAST('2023-01-01' AS DATE));
 
 DATEDIFF('2023-01-01', '2023-01-02', DAY);
 DATEDIFF(CAST('2023-01-01' AS DATETIME), CAST('2023-01-02' AS DATETIME), DAY);
+
+--------------------------------------
+-- Remove redundant casts
+--------------------------------------
+CAST(CAST('2023-01-01' AS DATE) AS DATE);
+CAST('2023-01-01' AS DATE);
+
+CAST(DATE_TRUNC('YEAR', CAST('2023-01-01' AS DATE)) AS DATE);
+DATE_TRUNC('YEAR', CAST('2023-01-01' AS DATE));
+
+DATE(DATE_TRUNC('YEAR', CAST("x" AS DATE)));
+DATE_TRUNC('YEAR', CAST("x" AS DATE));