postgresql7.1 select notification_id from notifications except select distinct notification_id from notifications inner join notification_requests using (type_id, object_id) left outer join notification_user_map using (notification_id, user_id) where sent_date is null select notification_id, notif_subject, notif_text, notif_html, user_id, type_id, delivery_method_id, response_id from notifications inner join notification_requests using (type_id, object_id) inner join acs_objects on (notification_requests.request_id = acs_objects.object_id) left outer join notification_user_map using (notification_id, user_id) where sent_date is null and creation_date <= notif_date and interval_id = :interval_id order by user_id, type_id