expression: fix wrong result for date add sub (#27244)

executor/executor_test.go

@@ -4969,6 +4969,16 @@ func (s *testSuiteP2) TestAddDateBuiltinWithWarnings(c *C) {
 	tk.MustQuery("show warnings").Check(testutil.RowsWithSep("|", "Warning|1292|Incorrect datetime value: '2001-01-00'"))
 }
 
+func (s *testSuiteP2) TestIssue27232(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 timestamp)")
+	tk.MustExec("insert into t values (\"1970-07-23 10:04:59\"), (\"2038-01-19 03:14:07\")")
+	tk.MustQuery("select * from t where date_sub(a, interval 10 month) = date_sub(\"1970-07-23 10:04:59\", interval 10 month)").Check(testkit.Rows("1970-07-23 10:04:59"))
+	tk.MustQuery("select * from t where timestampadd(hour, 1, a ) = timestampadd(hour, 1, \"2038-01-19 03:14:07\")").Check(testkit.Rows("2038-01-19 03:14:07"))
+}
+
 func (s *testSuiteP2) TestStrToDateBuiltinWithWarnings(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("set @@sql_mode='NO_ZERO_DATE'")

expression/builtin_time.go

@@ -3351,6 +3351,16 @@ func (c *addDateFunctionClass) getFunction(ctx sessionctx.Context, args []Expres
 		if err != nil {
 			return nil, err
 		}
+		if dateEvalTp == types.ETDatetime && args[0].GetType().Tp == mysql.TypeTimestamp {
+			tp := types.NewFieldType(mysql.TypeDatetime)
+			tp.Decimal = args[0].GetType().Decimal
+			tp.Flen = mysql.MaxDatetimeWidthNoFsp
+			if tp.Decimal > 0 {
+				tp.Flen = tp.Flen + 1 + tp.Decimal
+			}
+			types.SetBinChsClnFlag(tp)
+			args[0] = BuildCastFunction(ctx, args[0], tp)
+		}
 		bf.tp.Flen, bf.tp.Decimal = mysql.MaxDatetimeFullWidth, types.UnspecifiedLength
 	}
 
@@ -4025,6 +4035,16 @@ func (c *subDateFunctionClass) getFunction(ctx sessionctx.Context, args []Expres
 		if err != nil {
 			return nil, err
 		}
+		if dateEvalTp == types.ETDatetime && args[0].GetType().Tp == mysql.TypeTimestamp {
+			tp := types.NewFieldType(mysql.TypeDatetime)
+			tp.Decimal = args[0].GetType().Decimal
+			tp.Flen = mysql.MaxDatetimeWidthNoFsp
+			if tp.Decimal > 0 {
+				tp.Flen = tp.Flen + 1 + tp.Decimal
+			}
+			types.SetBinChsClnFlag(tp)
+			args[0] = BuildCastFunction(ctx, args[0], tp)
+		}
 		bf.tp.Flen, bf.tp.Decimal = mysql.MaxDatetimeFullWidth, types.UnspecifiedLength
 	}