Select distinct user_id from jb_screens where screen_id in (Select friend_screen_id from jb_friends where user_id = :user_id)
and user_id is not null
SELECT distinct p.person_id , p.first_names , p.last_name
FROM persons p
WHERE ( lower(p.last_name) like(lower('$user_prefix%')) OR lower(p.first_names) like(lower('$user_prefix%')) )
and p.person_id NOT IN ([template::util::tcl_to_sql_list $friends_list])