Removed unused EmptyResultSets in SQLCompilers.

Unused since ed1bcf05.

django/db/models/sql/compiler.py

@@ -482,10 +482,7 @@ class SQLCompiler(object):
                 not self.query.distinct_fields and
                 not self.query.select_for_update):
             obj.clear_ordering(True)
-        nested_sql = obj.get_compiler(connection=self.connection).as_sql(subquery=True)
-        if nested_sql == ('', ()):
-            raise EmptyResultSet
-        return nested_sql
+        return obj.get_compiler(connection=self.connection).as_sql(subquery=True)
 
     def get_default_columns(self, start_alias=None, opts=None, from_parent=None):
         """
@@ -1221,11 +1218,6 @@ class SQLAggregateCompiler(SQLCompiler):
         Creates the SQL for this query. Returns the SQL string and list of
         parameters.
         """
-        # Empty SQL for the inner query is a marker that the inner query
-        # isn't going to produce any results. This can happen when doing
-        # LIMIT 0 queries (generated by qs[:0]) for example.
-        if not self.query.subquery:
-            raise EmptyResultSet
         sql, params = [], []
         for annotation in self.query.annotation_select.values():
             ann_sql, ann_params = self.compile(annotation, select_format=True)