expression: handle ENUM in builtin function Values()

expression/builtin_other.go

@@ -615,13 +615,30 @@ func (b *builtinValuesStringSig) evalString(_ chunk.Row) (string, bool, error) {
 	if row.IsEmpty() {
 		return "", true, errors.New("Session current insert values is nil")
 	}
-	if b.offset < row.Len() {
-		if row.IsNull(b.offset) {
-			return "", true, nil
+	if b.offset >= row.Len() {
+		return "", true, errors.Errorf("Session current insert values len %d and column's offset %v don't match", row.Len(), b.offset)
+	}
+
+	if row.IsNull(b.offset) {
+		return "", true, nil
+	}
+
+	// Specially handle the ENUM/SET/BIT input value.
+	if retType := b.getRetTp(); retType.Hybrid() {
+		val := row.GetDatum(b.offset, retType)
+		res, err := val.ToString()
+		if err != nil {
+			return "", true, err
 		}
-		return row.GetString(b.offset), false, nil
+
+		resLen := len([]rune(res))
+		if b.ctx.GetSessionVars().StmtCtx.PadCharToFullLength && retType.Tp == mysql.TypeString && resLen < retType.Flen {
+			res = res + strings.Repeat(" ", retType.Flen-resLen)
+		}
+		return res, false, nil
 	}
-	return "", true, errors.Errorf("Session current insert values len %d and column's offset %v don't match", row.Len(), b.offset)
+
+	return row.GetString(b.offset), false, nil
 }
 
 type builtinValuesTimeSig struct {

expression/integration_test.go

@@ -3882,3 +3882,14 @@ func (s *testIntegrationSuite) TestValuesFloat32(c *C) {
 	tk.MustExec(`insert into t values (1, 0.02) on duplicate key update j = values (j);`)
 	tk.MustQuery(`select * from t;`).Check(testkit.Rows(`1 0.02`))
 }
+
+func (s *testIntegrationSuite) TestValuesEnum(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec(`drop table if exists t;`)
+	tk.MustExec(`create table t (a bigint primary key, b enum('a','b','c'));`)
+	tk.MustExec(`insert into t values (1, "a");`)
+	tk.MustQuery(`select * from t;`).Check(testkit.Rows(`1 a`))
+	tk.MustExec(`insert into t values (1, "b") on duplicate key update b = values(b);`)
+	tk.MustQuery(`select * from t;`).Check(testkit.Rows(`1 b`))
+}