planner/core: fix not null flag for using and natural join (#13735) (#…

…13739)
pingcap · Nov 26, 2019 · e8e0fe9 · e8e0fe9
1 parent ac4767a
commit e8e0fe9
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Showing 2 changed files with 12 additions and 5 deletions.
diff --git a/planner/core/integration_test.go b/planner/core/integration_test.go
@@ -106,7 +106,7 @@ func (s *testIntegrationSuite) runTestsWithTestData(caseName string, tk *testkit
 	}
 }
 
-func (s *testIntegrationSuite) TestApplyNotNullFlag(c *C) {
+func (s *testIntegrationSuite) TestJoinNotNullFlag(c *C) {
 	store, dom, err := newStoreWithBootstrap()
 	c.Assert(err, IsNil)
 	tk := testkit.NewTestKit(c, store)
@@ -121,6 +121,8 @@ func (s *testIntegrationSuite) TestApplyNotNullFlag(c *C) {
 	tk.MustExec("insert into t2 values (1)")
 
 	tk.MustQuery("select IFNULL((select t1.x from t1 where t1.x = t2.x), 'xxx') as col1 from t2").Check(testkit.Rows("xxx"))
+	tk.MustQuery("select ifnull(t1.x, 'xxx') from t2 left join t1 using(x)").Check(testkit.Rows("xxx"))
+	tk.MustQuery("select ifnull(t1.x, 'xxx') from t2 natural left join t1").Check(testkit.Rows("xxx"))
 }
 
 func (s *testIntegrationSuite) TestSimplifyOuterJoinWithCast(c *C) {

diff --git a/planner/core/logical_plan_builder.go b/planner/core/logical_plan_builder.go
@@ -480,7 +480,7 @@ func (b *PlanBuilder) buildUsingClause(p *LogicalJoin, leftPlan, rightPlan Logic
 	for _, col := range join.Using {
 		filter[col.Name.L] = true
 	}
-	return b.coalesceCommonColumns(p, leftPlan, rightPlan, join.Tp == ast.RightJoin, filter)
+	return b.coalesceCommonColumns(p, leftPlan, rightPlan, join.Tp, filter)
 }
 
 // buildNaturalJoin builds natural join output schema. It finds out all the common columns
@@ -490,15 +490,20 @@ func (b *PlanBuilder) buildUsingClause(p *LogicalJoin, leftPlan, rightPlan Logic
 // 	Every column in the first (left) table that is not a common column
 // 	Every column in the second (right) table that is not a common column
 func (b *PlanBuilder) buildNaturalJoin(p *LogicalJoin, leftPlan, rightPlan LogicalPlan, join *ast.Join) error {
-	return b.coalesceCommonColumns(p, leftPlan, rightPlan, join.Tp == ast.RightJoin, nil)
+	return b.coalesceCommonColumns(p, leftPlan, rightPlan, join.Tp, nil)
 }
 
 // coalesceCommonColumns is used by buildUsingClause and buildNaturalJoin. The filter is used by buildUsingClause.
-func (b *PlanBuilder) coalesceCommonColumns(p *LogicalJoin, leftPlan, rightPlan LogicalPlan, rightJoin bool, filter map[string]bool) error {
+func (b *PlanBuilder) coalesceCommonColumns(p *LogicalJoin, leftPlan, rightPlan LogicalPlan, joinTp ast.JoinType, filter map[string]bool) error {
 	lsc := leftPlan.Schema().Clone()
 	rsc := rightPlan.Schema().Clone()
+	if joinTp == ast.LeftJoin {
+		resetNotNullFlag(rsc, 0, rsc.Len())
+	} else if joinTp == ast.RightJoin {
+		resetNotNullFlag(lsc, 0, lsc.Len())
+	}
 	lColumns, rColumns := lsc.Columns, rsc.Columns
-	if rightJoin {
+	if joinTp == ast.RightJoin {
 		lColumns, rColumns = rsc.Columns, lsc.Columns
 	}