diff --git a/flaschengeist/plugins/balance/models.py b/flaschengeist/plugins/balance/models.py
index 23bb32c..1ba206b 100644
--- a/flaschengeist/plugins/balance/models.py
+++ b/flaschengeist/plugins/balance/models.py
@@ -40,7 +40,7 @@ class Transaction(db.Model, ModelSerializeMixin):
 
     @sender_id.expression
     def sender_id(cls):
-        return db.select([User.userid]).where(cls._sender_id == User.id_).as_scalar()
+        return db.select([User.userid]).where(cls._sender_id == User.id_).scalar_subquery()
 
     @hybrid_property
     def receiver_id(self):
@@ -48,7 +48,7 @@ class Transaction(db.Model, ModelSerializeMixin):
 
     @receiver_id.expression
     def receiver_id(cls):
-        return db.select([User.userid]).where(cls._receiver_id == User.id_).as_scalar()
+        return db.select([User.userid]).where(cls._receiver_id == User.id_).scalar_subquery()
 
     @property
     def author_id(self):