Make MySQL queries wrap set operations with parens (#782)

* Make MySQL queries wrap set operations with parens

* Add tests back

Author: pandaxtc

pypika/dialects.py

@@ -88,7 +88,7 @@ class MySQLQueryBuilder(QueryBuilder):
     QUERY_CLS = MySQLQuery
 
     def __init__(self, **kwargs: Any) -> None:
-        super().__init__(dialect=Dialects.MYSQL, wrap_set_operation_queries=False, **kwargs)
+        super().__init__(dialect=Dialects.MYSQL, **kwargs)
         self._duplicate_updates = []
         self._ignore_duplicates = False
         self._modifiers = []

pypika/tests/test_joins.py

@@ -845,12 +845,12 @@ def test_require_equal_number_of_fields(self):
         with self.assertRaises(SetOperationException):
             str(query1 + query2)
 
-    def test_mysql_query_does_not_wrap_unioned_queries_with_params(self):
+    def test_mysql_query_wraps_unioned_queries(self):
         query1 = MySQLQuery.from_(self.table1).select(self.table1.foo)
         query2 = Query.from_(self.table2).select(self.table2.bar)
 
         self.assertEqual(
-            "SELECT `foo` FROM `abc` UNION SELECT `bar` FROM `efg`",
+            "(SELECT `foo` FROM `abc`) UNION (SELECT `bar` FROM `efg`)",
             str(query1 + query2),
         )
 
@@ -968,12 +968,12 @@ def test_require_equal_number_of_fields_intersect(self):
         with self.assertRaises(SetOperationException):
             str(query1.intersect(query2))
 
-    def test_mysql_query_does_not_wrap_intersected_queries_with_params(self):
+    def test_mysql_query_wraps_intersected_queries(self):
         query1 = MySQLQuery.from_(self.table1).select(self.table1.foo)
         query2 = Query.from_(self.table2).select(self.table2.bar)
 
         self.assertEqual(
-            "SELECT `foo` FROM `abc` INTERSECT SELECT `bar` FROM `efg`",
+            "(SELECT `foo` FROM `abc`) INTERSECT (SELECT `bar` FROM `efg`)",
             str(query1.intersect(query2)),
         )
 
@@ -1064,12 +1064,12 @@ def test_require_equal_number_of_fields(self):
         with self.assertRaises(SetOperationException):
             str(query1.minus(query2))
 
-    def test_mysql_query_does_not_wrap_minus_queries_with_params(self):
+    def test_mysql_query_wraps_minus_queries(self):
         query1 = MySQLQuery.from_(self.table1).select(self.table1.foo)
         query2 = Query.from_(self.table2).select(self.table2.bar)
 
         self.assertEqual(
-            "SELECT `foo` FROM `abc` MINUS SELECT `bar` FROM `efg`",
+            "(SELECT `foo` FROM `abc`) MINUS (SELECT `bar` FROM `efg`)",
             str(query1 - query2),
         )