select name from mp3_playlists where playlist_id=$playlist_id
select title from mp3_mp3s where mp3_id=:new_mp3
select sort_key,
mp.title as title, map.mp3_id as mp3_id
from mp3_mp3_playlist_map map,
mp3_mp3s mp
where playlist_id=:playlist_id
and map.mp3_id=mp.mp3_id
order by sort_key