1 files changed, 6 insertions, 5 deletions
diff --git a/django/db/models/sql/aggregates.py b/django/db/models/sql/aggregates.py
index 75a330f22a..3c8720210b 100644
--- a/django/db/models/sql/aggregates.py
+++ b/django/db/models/sql/aggregates.py
@@ -73,22 +73,23 @@ class Aggregate(object):
             self.col = (change_map.get(self.col[0], self.col[0]), self.col[1])
 
     def as_sql(self, qn, connection):
-        "Return the aggregate, rendered as SQL."
+        "Return the aggregate, rendered as SQL with parameters."
+        params = []
 
         if hasattr(self.col, 'as_sql'):
-            field_name = self.col.as_sql(qn, connection)
+            field_name, params = self.col.as_sql(qn, connection)
         elif isinstance(self.col, (list, tuple)):
             field_name = '.'.join([qn(c) for c in self.col])
         else:
             field_name = self.col
 
-        params = {
+        substitutions = {
             'function': self.sql_function,
             'field': field_name
         }
-        params.update(self.extra)
+        substitutions.update(self.extra)
 
-        return self.sql_template % params
+        return self.sql_template % substitutions, params
 
 
 class Avg(Aggregate):