skip null row when deleting multiple tables

Signed-off-by: ekexium <[email protected]>

executor/delete.go

@@ -157,8 +157,21 @@ func (e *DeleteExec) doBatchDelete(ctx context.Context) error {
 }
 
 func (e *DeleteExec) composeTblRowMap(tblRowMap tableRowMapType, colPosInfos []plannercore.TblColPosInfo, joinedRow []types.Datum) error {
-	// iterate all the joined tables, and got the copresonding rows in joinedRow.
+	// iterate all the joined tables, and got the corresonding rows in joinedRow.
 	for _, info := range colPosInfos {
+		// if row[start..end] is a null row, which is possible in an outer join, we should not delete it.
+		nullRow := true
+		for _, d := range joinedRow[info.Start:info.End] {
+			if d.IsNull() {
+				continue
+			}
+			nullRow = false
+			break
+		}
+		if nullRow {
+			continue
+		}
+
 		if tblRowMap[info.TblID] == nil {
 			tblRowMap[info.TblID] = kv.NewHandleMap()
 		}

table/tables/tables_test.go

@@ -761,3 +761,17 @@ func TestConstraintCheckForOptimisticUntouched(t *testing.T) {
 	err = tk.ExecToErr("commit")
 	require.Error(t, err)
 }
+
+func TestAssertion(t *testing.T) {
+	store, clean := testkit.CreateMockStore(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table a (k1 int);")
+	tk.MustExec("create table b (id int primary key, k1 int);")
+	tk.MustExec("insert into a(k1) values(3);")
+	tk.MustExec("insert into b values(2, 2);")
+	tk.MustExec("insert into b values(0, 0);")
+	tk.MustExec("delete a,b from a left join b on a.k1 = b.k1")
+	tk.MustQuery("select * from b order by id").Check(testkit.Rows("0 0", "2 2"))
+}