diff --git a/addons/hr_holidays/hr_holidays.py b/addons/hr_holidays/hr_holidays.py
index 6a55403e960..793ab247a2d 100644
--- a/addons/hr_holidays/hr_holidays.py
+++ b/addons/hr_holidays/hr_holidays.py
@@ -510,8 +510,8 @@ class hr_employee(osv.osv):
             where
                 h.state='validate' and
                 s.limit=False and
-                h.employee_id in (%s)
-            group by h.employee_id"""% (','.join(map(str,ids)),) )
+                h.employee_id in %s
+            group by h.employee_id""", (tuple(ids),))
         res = cr.dictfetchall()
         remaining = {}
         for r in res: