From 993cadf0879294cadc6a8f39579d20e3725447ab Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Fri, 10 Sep 2021 16:38:39 +0800
Subject: [PATCH] planner: fix wrong plan caused by shallow copy schema columns
 (#27798) (#27836)

---
 planner/core/integration_test.go           | 30 ++++++++++++++++++++++
 planner/core/rule_aggregation_push_down.go |  2 +-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/planner/core/integration_test.go b/planner/core/integration_test.go
index 4957c29223fbb..8ef77e8eebf26 100644
--- a/planner/core/integration_test.go
+++ b/planner/core/integration_test.go
@@ -2095,3 +2095,33 @@ func (s *testIntegrationSuite) TestIssue26559(c *C) {
 	tk.MustExec("insert into t values('2020-07-29 09:07:01', '2020-07-27 16:57:36');")
 	tk.MustQuery("select greatest(a, b) from t union select null;").Sort().Check(testkit.Rows("2020-07-29 09:07:01", "<nil>"))
 }
+
+func (s *testIntegrationSuite) TestIssue27797(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t27797")
+	tk.MustExec("create table t27797(a int, b int, c int, d int) " +
+		"partition by range columns(d) (" +
+		"partition p0 values less than (20)," +
+		"partition p1 values less than(40)," +
+		"partition p2 values less than(60));")
+	tk.MustExec("insert into t27797 values(1,1,1,1), (2,2,2,2), (22,22,22,22), (44,44,44,44);")
+	tk.MustExec("set sql_mode='';")
+	result := tk.MustQuery("select count(*) from (select a, b from t27797 where d > 1 and d < 60 and b > 0 group by b, c) tt;")
+	result.Check(testkit.Rows("3"))
+
+	tk.MustExec("drop table if exists IDT_HP24172")
+	tk.MustExec("CREATE TABLE `IDT_HP24172` ( " +
+		"`COL1` mediumint(16) DEFAULT NULL, " +
+		"`COL2` varchar(20) DEFAULT NULL, " +
+		"`COL4` datetime DEFAULT NULL, " +
+		"`COL3` bigint(20) DEFAULT NULL, " +
+		"`COL5` float DEFAULT NULL, " +
+		"KEY `UM_COL` (`COL1`,`COL3`) " +
+		") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin " +
+		"PARTITION BY HASH( `COL1`+`COL3` ) " +
+		"PARTITIONS 8;")
+	tk.MustExec("insert into IDT_HP24172(col1) values(8388607);")
+	result = tk.MustQuery("select col2 from IDT_HP24172 where col1 = 8388607 and col1 in (select col1 from IDT_HP24172);")
+	result.Check(testkit.Rows("<nil>"))
+}
diff --git a/planner/core/rule_aggregation_push_down.go b/planner/core/rule_aggregation_push_down.go
index 0c796e4b0c3f4..8668efc2138dd 100644
--- a/planner/core/rule_aggregation_push_down.go
+++ b/planner/core/rule_aggregation_push_down.go
@@ -384,7 +384,7 @@ func (a *aggregationPushDownSolver) tryAggPushDownForUnion(union *LogicalUnionAl
 		}
 		newChildren = append(newChildren, newChild)
 	}
-	union.SetSchema(expression.NewSchema(newChildren[0].Schema().Columns...))
+	union.SetSchema(expression.NewSchema(newChildren[0].Schema().Clone().Columns...))
 	union.SetChildren(newChildren...)
 	return nil
 }