planner: update's select should not change the output columns (#12476) (

#12483)

go.mod

@@ -77,5 +77,3 @@ require (
 	sourcegraph.com/sourcegraph/appdash v0.0.0-20180531100431-4c381bd170b4
 	sourcegraph.com/sourcegraph/appdash-data v0.0.0-20151005221446-73f23eafcf67
 )
-
-go 1.13

planner/core/logical_plan_builder.go

@@ -2584,12 +2584,21 @@ func (b *PlanBuilder) buildUpdate(ctx context.Context, update *ast.UpdateStmt) (
 		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.SelectPriv, dbName, t.Name.L, "", nil)
 	}
 
+	oldSchemaLen := p.Schema().Len()
 	if sel.Where != nil {
-		p, err = b.buildSelection(ctx, p, sel.Where, nil)
+		p, err = b.buildSelection(ctx, p, update.Where, nil)
 		if err != nil {
 			return nil, err
 		}
 	}
+	// TODO: expression rewriter should not change the output columns. We should cut the columns here.
+	if p.Schema().Len() != oldSchemaLen {
+		proj := LogicalProjection{Exprs: expression.Column2Exprs(p.Schema().Columns[:oldSchemaLen])}.Init(b.ctx)
+		proj.SetSchema(expression.NewSchema(make([]*expression.Column, oldSchemaLen)...))
+		copy(proj.schema.Columns, p.Schema().Columns[:oldSchemaLen])
+		proj.SetChildren(p)
+		p = proj
+	}
 	if sel.OrderBy != nil {
 		p, err = b.buildSort(ctx, p, sel.OrderBy.Items, nil, nil)
 		if err != nil {

planner/core/logical_plan_test.go

@@ -940,6 +940,10 @@ func (s *testPlanSuite) TestPlanBuilder(c *C) {
 			// binlog columns, because the schema and data are not consistent.
 			plan: "LeftHashJoin{LeftHashJoin{TableReader(Table(t))->IndexLookUp(Index(t.c_d_e)[[666,666]], Table(t))}(test.t.a,test.t.b)->IndexReader(Index(t.c_d_e)[[42,42]])}(test.t.b,test.t.a)->Sel([or(6_aux_0, 10_aux_0)])->Projection->Delete",
 		},
+		{
+			sql:  "update t set a = 2 where b in (select c from t)",
+			plan: "LeftHashJoin{TableReader(Table(t))->IndexReader(Index(t.c_d_e)[[NULL,+inf]])->StreamAgg}(test.t.b,test.t.c)->Projection->Update",
+		},
 	}
 
 	ctx := context.Background()