simplify in comparison

Author: James Cor

sql/expression/comparison.go

@@ -141,7 +141,7 @@ func (c *comparison) Compare(ctx *sql.Context, row sql.Row) (int, error) {
 		return c.Left().Type().Compare(ctx, left, right)
 	}
 
-	l, r, compareType, err := c.CastLeftAndRight(ctx, left, right)
+	l, r, compareType, err := c.castLeftAndRight(ctx, left, right)
 	if err != nil {
 		return 0, err
 	}
@@ -171,7 +171,7 @@ func (c *comparison) evalLeftAndRight(ctx *sql.Context, row sql.Row) (interface{
 	return left, right, nil
 }
 
-func (c *comparison) CastLeftAndRight(ctx *sql.Context, left, right interface{}) (interface{}, interface{}, sql.Type, error) {
+func (c *comparison) castLeftAndRight(ctx *sql.Context, left, right interface{}) (interface{}, interface{}, sql.Type, error) {
 	leftType := c.Left().Type()
 	rightType := c.Right().Type()
 
@@ -452,7 +452,7 @@ func (e *NullSafeEquals) Compare(ctx *sql.Context, row sql.Row) (int, error) {
 	}
 
 	var compareType sql.Type
-	left, right, compareType, err = e.CastLeftAndRight(ctx, left, right)
+	left, right, compareType, err = e.castLeftAndRight(ctx, left, right)
 	if err != nil {
 		return 0, err
 	}

sql/expression/in.go

@@ -66,7 +66,6 @@ func (in *InTuple) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 	if err != nil {
 		return nil, err
 	}
-
 	if originalLeft == nil {
 		return nil, nil
 	}
@@ -85,6 +84,7 @@ func (in *InTuple) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 			}
 		}
 
+		leftLit := NewLiteral(originalLeft, in.Left().Type())
 		for _, el := range right {
 			originalRight, err := el.Eval(ctx, row)
 			if err != nil {
@@ -96,16 +96,11 @@ func (in *InTuple) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
 				continue
 			}
 
-			comp := newComparison(NewLiteral(originalLeft, in.Left().Type()), NewLiteral(originalRight, el.Type()))
-			l, r, compareType, err := comp.CastLeftAndRight(ctx, originalLeft, originalRight)
+			comp := newComparison(leftLit, NewLiteral(originalRight, el.Type()))
+			cmp, err := comp.Compare(ctx, row)
 			if err != nil {
 				return nil, err
 			}
-			cmp, err := compareType.Compare(ctx, l, r)
-			if err != nil {
-				return nil, err
-			}
-
 			if cmp == 0 {
 				return true, nil
 			}