diff --git a/parser/parser.y b/parser/parser.y
index 99283183964b9..d45e1e00aff7e 100644
--- a/parser/parser.y
+++ b/parser/parser.y
@@ -2687,10 +2687,6 @@ QuickOptional:
 		$$ = true
 	}
 
-semiOpt:
-	/* EMPTY */
-|	';'
-
 
 /***************************Prepared Statement Start******************************
  * See: https://dev.mysql.com/doc/refman/5.7/en/prepare.html
@@ -2879,9 +2875,13 @@ TableFactor:
 	{
 		$$ = &rsets.TableSource{Source: $1, Name: $2.(string)}
 	}
-|	'(' SelectStmt semiOpt ')' AsOpt
+|	'(' SelectStmt ')' AsOpt
 	{
-		$$ = &rsets.TableSource{Source: $2, Name: $5.(string)}
+		$$ = &rsets.TableSource{Source: $2, Name: $4.(string)}
+	}
+|	'(' UnionStmt ')' AsOpt
+	{
+		$$ = &rsets.TableSource{Source: $2, Name: $4.(string)}
 	}
 |	'(' TableRefs ')'
 	{
@@ -3035,6 +3035,14 @@ SubSelect:
 		s.SetText(src[yyS[yypt-1].offset-1:yyS[yypt].offset-1])
 		$$ = &subquery.SubQuery{Stmt: s}
 	}
+|	'(' UnionStmt ')'
+	{
+		s := $2.(*stmts.UnionStmt)
+		src := yylex.(*lexer).src
+		// See the implemention of yyParse function
+		s.SetText(src[yyS[yypt-1].offset-1:yyS[yypt].offset-1])
+		$$ = &subquery.SubQuery{Stmt: s}
+	}
 
 // See: https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html
 SelectLockOpt:
diff --git a/parser/parser_test.go b/parser/parser_test.go
index 7ed6a384094b4..560d0b95a4332 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -483,6 +483,8 @@ func (s *testParserSuite) TestParser0(c *C) {
 		{"(select c1 from t1) union (select c2 from t2) order by c1 union select c3 from t3", false},
 		{"(select c1 from t1) union (select c2 from t2) limit 1 union select c3 from t3", false},
 		{"(select c1 from t1) union select c2 from t2 union (select c3 from t3) order by c1 limit 1", true},
+		{"select (select 1 union select 1) as a", true},
+		{"select * from (select 1 union select 2) as a", true},
 	}
 
 	for _, t := range table {