planner: fix Uncertain Results caused by MERGE_JOIN (#47078)

close #46580

Author: qw4990

planner/core/integration_test.go

@@ -620,6 +620,20 @@ func TestINLJHintSmallTable(t *testing.T) {
 	tk.MustExec("explain format = 'brief' select /*+ TIDB_INLJ(t1) */ * from t1 join t2 on t1.a = t2.a")
 }
 
+func TestIssue46580(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec(`CREATE TABLE t0(c0 INT);`)
+	tk.MustExec(`CREATE TABLE t1(c0 BOOL, c1 BOOL);`)
+	tk.MustExec(`INSERT INTO t1 VALUES (false, true);`)
+	tk.MustExec(`INSERT INTO t1 VALUES (true, true);`)
+	tk.MustExec(`CREATE definer='root'@'localhost'  VIEW v0(c0, c1, c2) AS SELECT t1.c0, LOG10(t0.c0), t1.c0 FROM t0, t1;`)
+	tk.MustExec(`INSERT INTO t0(c0) VALUES (3);`)
+	tk.MustQuery(`SELECT /*+ MERGE_JOIN(t1, t0, v0)*/v0.c2, t1.c0 FROM v0,  t0 CROSS JOIN t1 ORDER BY -v0.c1;`).Sort().Check(
+		testkit.Rows(`0 0`, `0 1`, `1 0`, `1 1`))
+}
+
 func TestInvisibleIndex(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)

planner/core/rule_inject_extra_projection.go

@@ -264,6 +264,7 @@ func InjectProjBelowSort(p PhysicalPlan, orderByItems []*util.ByItems) PhysicalP
 	if origChildProj, isChildProj := childPlan.(*PhysicalProjection); isChildProj {
 		refine4NeighbourProj(bottomProj, origChildProj)
 	}
+	refine4NeighbourProj(topProj, bottomProj)
 
 	return topProj
 }
@@ -325,6 +326,7 @@ func TurnNominalSortIntoProj(p PhysicalPlan, onlyColumn bool, orderByItems []*ut
 	if origChildProj, isChildProj := childPlan.(*PhysicalProjection); isChildProj {
 		refine4NeighbourProj(bottomProj, origChildProj)
 	}
+	refine4NeighbourProj(topProj, bottomProj)
 
 	return topProj
 }