diff --git a/auth_dynamic_groups/model/res_users.py b/auth_dynamic_groups/model/res_users.py
index 8ce916e19..bcfd2d0ad 100644
--- a/auth_dynamic_groups/model/res_users.py
+++ b/auth_dynamic_groups/model/res_users.py
@@ -40,9 +40,12 @@ class res_users(Model):
             dynamic_groups = groups_obj.browse(
                 cr, SUPERUSER_ID, groups_obj.search(
                     cr, SUPERUSER_ID, [('is_dynamic', '=', True)]))
-            cr.execute(
-                'delete from res_groups_users_rel where uid=%s and gid in %s',
-                (uid, tuple(dynamic_groups.ids)))
+            if dynamic_groups:
+                cr.execute(
+                    'delete from res_groups_users_rel '
+                    'where uid=%s and gid in %s',
+                    (uid, tuple(dynamic_groups.ids))
+                )
             for dynamic_group in dynamic_groups:
                 if dynamic_group.eval_dynamic_group_condition(uid=uid):
                     cr.execute(