expression: truncate time part for current_date columns

pkg/expression/helper.go

@@ -92,14 +92,22 @@ func GetTimeValue(ctx BuildContext, v any, tp byte, fsp int, explicitTz *time.Lo
 	switch x := v.(type) {
 	case string:
 		lowerX := strings.ToLower(x)
-		if lowerX == ast.CurrentTimestamp || lowerX == ast.CurrentDate {
+		switch lowerX {
+		case ast.CurrentTimestamp:
 			if value, err = getTimeCurrentTimeStamp(ctx.GetEvalCtx(), tp, fsp); err != nil {
 				return d, err
 			}
-		} else if lowerX == types.ZeroDatetimeStr {
+		case ast.CurrentDate:
+			if value, err = getTimeCurrentTimeStamp(ctx.GetEvalCtx(), tp, fsp); err != nil {
+				return d, err
+			}
+			yy, mm, dd := value.Year(), value.Month(), value.Day()
+			truncated := types.FromDate(yy, mm, dd, 0, 0, 0, 0)
+			value.SetCoreTime(truncated)
+		case types.ZeroDatetimeStr:
 			value, err = types.ParseTimeFromNum(tc, 0, tp, fsp)
 			terror.Log(err)
-		} else {
+		default:
 			value, err = types.ParseTime(tc, x, tp, fsp)
 			if err != nil {
 				return d, err

tests/integrationtest/r/executor/write.result

@@ -2146,3 +2146,9 @@ Error 1364 (HY000): Field 'pk' doesn't have a default value
 replace t2 set c=default(a);
 Error 3105 (HY000): The value specified for generated column 'c' in table 't2' is not allowed.
 drop table t1, t2;
+drop table if exists t;
+create table t (a date default current_date);
+insert into t values();
+select count(1) from t where a = date(now());
+count(1)
+1

tests/integrationtest/t/executor/write.test

@@ -1350,3 +1350,8 @@ replace t2 set a=default(a), c=default(c);
 replace t2 set c=default(a);
 drop table t1, t2;
 
+# TestIssue53746
+drop table if exists t;
+create table t (a date default current_date);
+insert into t values();
+select count(1) from t where a = date(now());