diff -r e821a1ae9773 -r 75f8f05f9a60 web/hdalab/views/ajax.py
--- a/web/hdalab/views/ajax.py	Fri Mar 02 10:48:26 2012 +0100
+++ b/web/hdalab/views/ajax.py	Fri Mar 02 23:25:56 2012 +0100
@@ -170,7 +170,15 @@
     else:
         contenus = contenus.values()
 
-    tagqs = tagqs.annotate(nb=Count('datasheet')).order_by('-nb')[:tag_count]
+    #tagqs = tagqs.annotate(nb=Count('datasheet')).order_by('-nb')[:tag_count]
+    tagqs = tagqs.annotate(nb=Count('datasheet')).order_by('-nb').only('id','label')[:tag_count]
+    # hack to add only necessary fileds in the group by
+    # contournement bug https://code.djangoproject.com/ticket/17144
+    tagqs.query.clear_select_fields()
+    tagqs.query.add_fields(['id','label'], False)
+    tagqs.query.set_group_by()
+
+    #hack : django bug
 
     tags = [{'id': tag.id, 'label': tag.label, 'score': tag.nb} for tag in tagqs]