expression: don't propagateColumnEQ joinCondition when nullSensitive (#…

…23989) (#24022)

expression/constant_propagation.go

@@ -533,6 +533,9 @@ func (s *propOuterJoinConstSolver) deriveConds(outerCol, innerCol *Column, schem
 // 'expression(..., outerCol, ...)' does not reference columns outside children schemas of join node.
 // Derived new expressions must be appended into join condition, not filter condition.
 func (s *propOuterJoinConstSolver) propagateColumnEQ() {
+	if s.nullSensitive {
+		return
+	}
 	visited := make([]bool, 2*len(s.joinConds)+len(s.filterConds))
 	s.unionSet = disjointset.NewIntSet(len(s.columns))
 	var outerCol, innerCol *Column
@@ -553,9 +556,6 @@ func (s *propOuterJoinConstSolver) propagateColumnEQ() {
 			// `select *, t1.a in (select t2.b from t t2) from t t1`
 			// rows with t2.b is null would impact whether LeftOuterSemiJoin should output 0 or null if there
 			// is no row satisfying t2.b = t1.a
-			if s.nullSensitive {
-				continue
-			}
 			childCol := s.innerSchema.RetrieveColumn(innerCol)
 			if !mysql.HasNotNullFlag(childCol.RetType.Flag) {
 				notNullExpr := BuildNotNullExpr(s.ctx, childCol)

expression/integration_test.go

@@ -8096,3 +8096,17 @@ func (s *testIntegrationSuite) TestApproximatePercentile(c *C) {
 	tk.MustExec("insert into t values(b'1111')")
 	tk.MustQuery("select approx_percentile(a, 10) from t").Check(testkit.Rows("<nil>"))
 }
+
+func (s *testIntegrationSuite) TestIssue23889(c *C) {
+	defer s.cleanEnv(c)
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists test_decimal,test_t;")
+	tk.MustExec("create table test_decimal(col_decimal decimal(10,0));")
+	tk.MustExec("insert into test_decimal values(null),(8);")
+	tk.MustExec("create table test_t(a int(11), b decimal(32,0));")
+	tk.MustExec("insert into test_t values(1,4),(2,4),(5,4),(7,4),(9,4);")
+
+	tk.MustQuery("SELECT ( test_decimal . `col_decimal` , test_decimal . `col_decimal` )  IN ( select * from test_t ) as field1 FROM  test_decimal;").Check(
+		testkit.Rows("<nil>", "0"))
+}