How many tracks are there?
select count(*) from tracks;
How many are in a playlist of a Movie?
select count(*) from tracks as t1 join playlist_tracks as t2 on t1.id = t2.track_id join playlists as t3 on t3.id = t2.playlist_id where t3.name = "Movies";
Which ones ?
select t1.name from tracks as t1 join playlist_tracks as t2 on t1.id = t2.track_id join playlists as t3 on t3.id = t2.playlist_id where t3.name = "Movies";