planner: fix wrong behavior for != any() (#20058) (#20062)

cmd/explaintest/r/select.result

@@ -384,7 +384,7 @@ explain select a != any (select a from t t2) from t t1;
 id	estRows	task	access object	operator info
 Projection_8	10000.00	root		and(or(or(gt(Column#8, 1), ne(test.t.a, Column#7)), if(ne(Column#9, 0), <nil>, 0)), and(ne(Column#10, 0), if(isnull(test.t.a), <nil>, 1)))->Column#11
 └─HashJoin_9	10000.00	root		CARTESIAN inner join
-  ├─StreamAgg_14(Build)	1.00	root		funcs:firstrow(Column#13)->Column#7, funcs:count(distinct Column#14)->Column#8, funcs:sum(Column#15)->Column#9, funcs:count(1)->Column#10
+  ├─StreamAgg_14(Build)	1.00	root		funcs:max(Column#13)->Column#7, funcs:count(distinct Column#14)->Column#8, funcs:sum(Column#15)->Column#9, funcs:count(1)->Column#10
   │ └─Projection_19	10000.00	root		test.t.a, test.t.a, cast(isnull(test.t.a), decimal(65,0) BINARY)->Column#15
   │   └─TableReader_18	10000.00	root		data:TableFullScan_17
   │     └─TableFullScan_17	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo

planner/core/expression_rewriter.go

@@ -639,7 +639,9 @@ func (er *expressionRewriter) buildQuantifierPlan(plan4Agg *LogicalAggregation,
 // t.id != s.id or count(distinct s.id) > 1 or [any checker]. If there are two different values in s.id ,
 // there must exist a s.id that doesn't equal to t.id.
 func (er *expressionRewriter) handleNEAny(lexpr, rexpr expression.Expression, np LogicalPlan) {
-	firstRowFunc, err := aggregation.NewAggFuncDesc(er.sctx, ast.AggFuncFirstRow, []expression.Expression{rexpr}, false)
+	// If there is NULL in s.id column, s.id should be the value that isn't null in condition t.id != s.id.
+	// So use function max to filter NULL.
+	maxFunc, err := aggregation.NewAggFuncDesc(er.sctx, ast.AggFuncMax, []expression.Expression{rexpr}, false)
 	if err != nil {
 		er.err = err
 		return
@@ -650,24 +652,24 @@ func (er *expressionRewriter) handleNEAny(lexpr, rexpr expression.Expression, np
 		return
 	}
 	plan4Agg := LogicalAggregation{
-		AggFuncs: []*aggregation.AggFuncDesc{firstRowFunc, countFunc},
+		AggFuncs: []*aggregation.AggFuncDesc{maxFunc, countFunc},
 	}.Init(er.sctx, er.b.getSelectOffset())
 	if hint := er.b.TableHints(); hint != nil {
 		plan4Agg.aggHints = hint.aggHints
 	}
 	plan4Agg.SetChildren(np)
-	firstRowResultCol := &expression.Column{
+	maxResultCol := &expression.Column{
 		UniqueID: er.sctx.GetSessionVars().AllocPlanColumnID(),
-		RetType:  firstRowFunc.RetTp,
+		RetType:  maxFunc.RetTp,
 	}
 	count := &expression.Column{
 		UniqueID: er.sctx.GetSessionVars().AllocPlanColumnID(),
 		RetType:  countFunc.RetTp,
 	}
 	plan4Agg.names = append(plan4Agg.names, types.EmptyName, types.EmptyName)
-	plan4Agg.SetSchema(expression.NewSchema(firstRowResultCol, count))
+	plan4Agg.SetSchema(expression.NewSchema(maxResultCol, count))
 	gtFunc := expression.NewFunctionInternal(er.sctx, ast.GT, types.NewFieldType(mysql.TypeTiny), count, expression.NewOne())
-	neCond := expression.NewFunctionInternal(er.sctx, ast.NE, types.NewFieldType(mysql.TypeTiny), lexpr, firstRowResultCol)
+	neCond := expression.NewFunctionInternal(er.sctx, ast.NE, types.NewFieldType(mysql.TypeTiny), lexpr, maxResultCol)
 	cond := expression.ComposeDNFCondition(er.sctx, gtFunc, neCond)
 	er.buildQuantifierPlan(plan4Agg, cond, lexpr, rexpr, false)
 }

planner/core/expression_rewriter_test.go

@@ -260,3 +260,26 @@ func (s *testExpressionRewriterSuite) TestPatternLikeToExpression(c *C) {
 	tk.MustQuery("select 0 like '0';").Check(testkit.Rows("1"))
 	tk.MustQuery("select 0.00 like '0.00';").Check(testkit.Rows("1"))
 }
+
+func (s *testExpressionRewriterSuite) TestIssue20007(c *C) {
+	defer testleak.AfterTest(c)()
+	store, dom, err := newStoreWithBootstrap()
+	c.Assert(err, IsNil)
+	tk := testkit.NewTestKit(c, store)
+	defer func() {
+		dom.Close()
+		store.Close()
+	}()
+
+	tk.MustExec("use test;")
+	tk.MustExec("drop table if exists t1, t2;")
+	tk.MustExec("create table t1 (c_int int, c_str varchar(40), c_datetime datetime, primary key(c_int));")
+	tk.MustExec("create table t2 (c_int int, c_str varchar(40), c_datetime datetime, primary key (c_datetime)) partition by range (to_days(c_datetime)) ( partition p0 values less than (to_days('2020-02-01')), partition p1 values less than (to_days('2020-04-01')), partition p2 values less than (to_days('2020-06-01')), partition p3 values less than maxvalue);")
+	tk.MustExec("insert into t1 (c_int, c_str, c_datetime) values (1, 'xenodochial bassi', '2020-04-29 03:22:51'), (2, 'epic wiles', '2020-01-02 23:29:51'), (3, 'silly burnell', '2020-02-25 07:43:07');")
+	tk.MustExec("insert into t2 (c_int, c_str, c_datetime) values (1, 'trusting matsumoto', '2020-01-07 00:57:18'), (2, 'pedantic boyd', '2020-06-08 23:12:16'), (null, 'strange hypatia', '2020-05-23 17:45:27');")
+	// Test 10 times.
+	for i := 0; i < 10; i++ {
+		tk.MustQuery("select * from t1 where c_int != any (select c_int from t2 where t1.c_str <= t2.c_str); ").Check(
+			testkit.Rows("2 epic wiles 2020-01-02 23:29:51", "3 silly burnell 2020-02-25 07:43:07"))
+	}
+}