Merge branch 'master' into bugfix/mismatch

expression/constant_propagation.go

@@ -147,7 +147,7 @@ func tryToReplaceCond(ctx sessionctx.Context, src *Column, tgt *Column, cond Exp
 			sf.FuncName.L == ast.If ||
 			sf.FuncName.L == ast.Case ||
 			sf.FuncName.L == ast.NullEQ) {
-		return false, false, cond
+		return false, true, cond
 	}
 	for idx, expr := range sf.GetArgs() {
 		if src.Equal(nil, expr) {

expression/integration_test.go

@@ -10173,3 +10173,21 @@ func (s *testIntegrationSuite) TestIssue26958(c *C) {
 	tk.MustQuery("select \n(select count(distinct c_int) from t2 where c_int >= t1.c_int) c1, \n(select count(distinct c_int) from t2 where c_int >= t1.c_int) c2\nfrom t1 group by c_int;\n").
 		Check(testkit.Rows("3 3", "2 2", "1 1"))
 }
+
+func (s *testIntegrationSuite) TestConstPropNullFunctions(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t1, t2")
+	tk.MustExec("create table t1 (a integer)")
+	tk.MustExec("insert into t1 values (0), (1), (2), (3)")
+	tk.MustExec("create table t2 (a integer, b integer)")
+	tk.MustExec("insert into t2 values (0,1), (1,1), (2,1), (3,1)")
+	tk.MustQuery("select t1.* from t1 left join t2 on t2.a = t1.a where t1.a = ifnull(t2.b, 0)").Check(testkit.Rows("1"))
+
+	tk.MustExec("drop table if exists t1, t2")
+	tk.MustExec("create table t1 (i1 integer, c1 char)")
+	tk.MustExec("insert into t1 values (2, 'a'), (1, 'b'), (3, 'c'), (0, null);")
+	tk.MustExec("create table t2 (i2 integer, c2 char, f2 float)")
+	tk.MustExec("insert into t2 values (0, 'c', null), (1, null, 0.1), (3, 'b', 0.01), (2, 'q', 0.12), (null, 'a', -0.1), (null, null, null)")
+	tk.MustQuery("select * from t2 where t2.i2=((select count(1) from t1 where t1.i1=t2.i2))").Check(testkit.Rows("1 <nil> 0.1"))
+}

meta/main_test.go

@@ -0,0 +1,30 @@
+// Copyright 2021 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package meta
+
+import (
+	"testing"
+
+	"github.com/pingcap/tidb/util/testbridge"
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	testbridge.WorkaroundGoCheckFlags()
+	opts := []goleak.Option{
+		goleak.IgnoreTopFunction("go.opencensus.io/stats/view.(*worker).start"),
+		goleak.IgnoreTopFunction("go.etcd.io/etcd/pkg/logutil.(*MergeLogger).outputLoop"),
+	}
+	goleak.VerifyTestMain(m, opts...)
+}