diff options
Diffstat (limited to 'django/db/models/sql/query.py')
| -rw-r--r-- | django/db/models/sql/query.py | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py index ec477447f3..c0449e7047 100644 --- a/django/db/models/sql/query.py +++ b/django/db/models/sql/query.py @@ -337,7 +337,7 @@ class Query(object): # information but retrieves only the first row. Aggregate # over the subquery instead. if self.group_by is not None: - from subqueries import AggregateQuery + from django.db.models.sql.subqueries import AggregateQuery query = AggregateQuery(self.model) obj = self.clone() @@ -349,7 +349,13 @@ class Query(object): query.aggregate_select[alias] = aggregate del obj.aggregate_select[alias] - query.add_subquery(obj, using) + try: + query.add_subquery(obj, using) + except EmptyResultSet: + return dict( + (alias, None) + for alias in query.aggregate_select + ) else: query = self self.select = [] @@ -382,13 +388,19 @@ class Query(object): # If a select clause exists, then the query has already started to # specify the columns that are to be returned. # In this case, we need to use a subquery to evaluate the count. - from subqueries import AggregateQuery + from django.db.models.sql.subqueries import AggregateQuery subquery = obj subquery.clear_ordering(True) subquery.clear_limits() obj = AggregateQuery(obj.model) - obj.add_subquery(subquery, using=using) + try: + obj.add_subquery(subquery, using=using) + except EmptyResultSet: + # add_subquery evaluates the query, if it's an EmptyResultSet + # then there are can be no results, and therefore there the + # count is obviously 0 + return 0 obj.add_count_column() number = obj.get_aggregation(using=using)[None] |