Ticket #3732: count_distinct.patch

query.py

@@ -223 +223 @@
 
         cursor = connection.cursor()
         if self._distinct:
-            id_col = "%s.%s" % (backend.quote_name(self.model._meta.db_table),
-                    backend.quote_name(self.model._meta.pk.column))
-            cursor.execute("SELECT COUNT(DISTINCT(%s))" % id_col + sql, params)
+            if self._fields:
+                columns = [self.model._meta.get_field(f, many_to_many=False).column for f in self._fields]
+                select = ['%s.%s' % (backend.quote_name(self.model._meta.db_table), backend.quote_name(c)) for c in columns]
+                distinct_expr = "||".join(select)
+                cursor.execute("SELECT COUNT(DISTINCT(%s))" % distinct_expr + sql, params)
+            else:
+                id_col = "%s.%s" % (backend.quote_name(self.model._meta.db_table),
+                        backend.quote_name(self.model._meta.pk.column))
+                cursor.execute("SELECT COUNT(DISTINCT(%s))" % id_col + sql, params)
         else:
             cursor.execute("SELECT COUNT(*)" + sql, params)
         count = cursor.fetchone()[0]