planner: fix wrong plan caused by shallow copy schema columns

planner/core/integration_test.go

@@ -4408,3 +4408,18 @@ func (s *testIntegrationSerialSuite) TestPushDownGroupConcatToTiFlash(c *C) {
  res.Check(testkit.Rows(output[i].Plan...))
  }
 }
+
+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"))
+}

planner/core/rule_aggregation_push_down.go

@@ -388,7 +388,7 @@ 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
 }