diff --git a/executor/index_lookup_merge_join_test.go b/executor/index_lookup_merge_join_test.go
index 2158026f1966f..1817dca79a3ae 100644
--- a/executor/index_lookup_merge_join_test.go
+++ b/executor/index_lookup_merge_join_test.go
@@ -159,13 +159,21 @@ func (s *testSuite9) TestIssue20549(c *C) {
 		testkit.Rows("1"))
 }
 
-func (s *testSuite9) TestIssue24473(c *C) {
+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;").Check(
-		testkit.Rows("y y", "b b", "x x", "x x", "x x", "x x"))
-	tk.MustQuery("SELECT /*+ inl_merge_join (t2,t3) */ t2.a,t3.a FROM x t2 inner join x t3 on t2.a = t3.a;").Check(
-		testkit.Rows("y y", "b b", "x x", "x x", "x x", "x x"))
+	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"))
 }
diff --git a/planner/core/exhaust_physical_plans.go b/planner/core/exhaust_physical_plans.go
index 59b635eada379..9dffea4e21c7c 100644
--- a/planner/core/exhaust_physical_plans.go
+++ b/planner/core/exhaust_physical_plans.go
@@ -150,14 +150,15 @@ func (p *LogicalJoin) GetMergeJoin(prop *property.PhysicalProperty, schema *expr
 	// The leftProperties caches all the possible properties that are provided by its children.
 	leftJoinKeys, rightJoinKeys, isNullEQ, hasNullEQ := p.GetJoinKeys()
 
-	// EnumType Unsupported: merge join conflicts with index order. ref: https://github.com/pingcap/tidb/issues/24473
+	// 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 {
+		if leftKey.RetType.Tp == mysql.TypeEnum || leftKey.RetType.Tp == mysql.TypeSet {
 			return nil
 		}
 	}
 	for _, rightKey := range rightJoinKeys {
-		if rightKey.RetType.Tp == mysql.TypeEnum {
+		if rightKey.RetType.Tp == mysql.TypeEnum || rightKey.RetType.Tp == mysql.TypeSet {
 			return nil
 		}
 	}
@@ -529,14 +530,15 @@ func (p *LogicalJoin) constructIndexMergeJoin(
 			return nil
 		}
 
-		// EnumType Unsupported: merge join conflicts with index order. ref: https://github.com/pingcap/tidb/issues/24473
+		// 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 {
+			if innerKey.RetType.Tp == mysql.TypeEnum || innerKey.RetType.Tp == mysql.TypeSet {
 				return nil
 			}
 		}
 		for _, outerKey := range join.OuterJoinKeys {
-			if outerKey.RetType.Tp == mysql.TypeEnum {
+			if outerKey.RetType.Tp == mysql.TypeEnum || outerKey.RetType.Tp == mysql.TypeSet {
 				return nil
 			}
 		}