cherry pick pingcap#25672 to release-5.0

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

executor/index_lookup_merge_join_test.go

@@ -158,3 +158,25 @@ func (s *testSuite9) TestIssue20549(c *C) {
 	tk.MustQuery("SELECT /*+ HASH_JOIN(t1,t2)  */ 1 from t1 left outer join t2 on t1.t2id=t2.id;\n").Check(
 		testkit.Rows("1"))
 }
+<<<<<<< HEAD
+=======
+
+func (s *testSuite9) TestIssue24473AndIssue25669(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("drop table if exists x, t2, t3")
+	tk.MustExec("CREATE TABLE `x` (  `a` enum('y','b','1','x','0','null') DEFAULT NULL,  KEY `a` (`a`));")
+	tk.MustExec("insert into x values(\"x\"),(\"x\"),(\"b\"),(\"y\");")
+	tk.MustQuery("SELECT /*+ merge_join (t2,t3) */ t2.a,t3.a FROM x t2 inner join x t3 on t2.a = t3.a;").Sort().Check(
+		testkit.Rows("b b", "x x", "x x", "x x", "x x", "y y"))
+	tk.MustQuery("SELECT /*+ inl_merge_join (t2,t3) */ t2.a,t3.a FROM x t2 inner join x t3 on t2.a = t3.a;").Sort().Check(
+		testkit.Rows("b b", "x x", "x x", "x x", "x x", "y y"))
+
+	tk.MustExec("drop table if exists x, t2, t3")
+	tk.MustExec("CREATE TABLE `x` (  `a` set('y','b','1','x','0','null') DEFAULT NULL,  KEY `a` (`a`));")
+	tk.MustExec("insert into x values(\"x\"),(\"x\"),(\"b\"),(\"y\");")
+	tk.MustQuery("SELECT /*+ merge_join (t2,t3) */ t2.a,t3.a FROM x t2 inner join x t3 on t2.a = t3.a;").Sort().Check(
+		testkit.Rows("b b", "x x", "x x", "x x", "x x", "y y"))
+	tk.MustQuery("SELECT /*+ inl_merge_join (t2,t3) */ t2.a,t3.a FROM x t2 inner join x t3 on t2.a = t3.a;").Sort().Check(
+		testkit.Rows("b b", "x x", "x x", "x x", "x x", "y y"))
+}
+>>>>>>> 574de5e5e... planner: fix incorrect result of set type for merge join (#25672)

planner/core/exhaust_physical_plans.go

@@ -148,6 +148,23 @@ func (p *LogicalJoin) GetMergeJoin(prop *property.PhysicalProperty, schema *expr
 	joins := make([]PhysicalPlan, 0, len(p.leftProperties)+1)
 	// The leftProperties caches all the possible properties that are provided by its children.
 	leftJoinKeys, rightJoinKeys, isNullEQ, hasNullEQ := p.GetJoinKeys()
+<<<<<<< HEAD
+=======
+
+	// EnumType/SetType Unsupported: merge join conflicts with index order.
+	// ref: https://github.com/pingcap/tidb/issues/24473, https://github.com/pingcap/tidb/issues/25669
+	for _, leftKey := range leftJoinKeys {
+		if leftKey.RetType.Tp == mysql.TypeEnum || leftKey.RetType.Tp == mysql.TypeSet {
+			return nil
+		}
+	}
+	for _, rightKey := range rightJoinKeys {
+		if rightKey.RetType.Tp == mysql.TypeEnum || rightKey.RetType.Tp == mysql.TypeSet {
+			return nil
+		}
+	}
+
+>>>>>>> 574de5e5e... planner: fix incorrect result of set type for merge join (#25672)
 	// TODO: support null equal join keys for merge join
 	if hasNullEQ {
 		return nil
@@ -514,6 +531,23 @@ func (p *LogicalJoin) constructIndexMergeJoin(
 		if len(join.InnerHashKeys) > len(join.InnerJoinKeys) {
 			return nil
 		}
+<<<<<<< HEAD
+=======
+
+		// EnumType/SetType Unsupported: merge join conflicts with index order.
+		// ref: https://github.com/pingcap/tidb/issues/24473, https://github.com/pingcap/tidb/issues/25669
+		for _, innerKey := range join.InnerJoinKeys {
+			if innerKey.RetType.Tp == mysql.TypeEnum || innerKey.RetType.Tp == mysql.TypeSet {
+				return nil
+			}
+		}
+		for _, outerKey := range join.OuterJoinKeys {
+			if outerKey.RetType.Tp == mysql.TypeEnum || outerKey.RetType.Tp == mysql.TypeSet {
+				return nil
+			}
+		}
+
+>>>>>>> 574de5e5e... planner: fix incorrect result of set type for merge join (#25672)
 		hasPrefixCol := false
 		for _, l := range join.IdxColLens {
 			if l != types.UnspecifiedLength {