select pretty_name from adv_groups where group_key = :group_key select group_key, pretty_name from adv_groups where not group_key in (select group_key from adv_group_map) select map.group_key, advs.adv_key from advs, adv_group_map map where advs.adv_key = map.adv_key UNION select NULL, advs.adv_key from advs where 0=(select count(*) from adv_group_map where advs.adv_key = adv_group_map.adv_key)