Fix subquery.

accountant/models/accounts.py

@@ -195,7 +195,7 @@ class Account(db.Model):
             )
 
             if end:
-                query = query.filter(query.c.operation_date <= str(end))
+                query = query.filter(base_query.c.operation_date <= str(end))
 
         elif end:
             query = query.filter(Operation.operation_date <= str(end))