How many different playlist are there?
select count(*) from playlists;
What are they?
select name from playlists;
What are the tracks in each one?
select t1.name, t3.name from tracks as t1 join playlist_tracks as t2 on t1.id = t2.track_id join playlists as t3 on t2.playlist_id = t3.id;
What are the names of the ones are in both Movies and music!
select t1.name from tracks as t1 join playlist_tracks as t2 on t1.id = t2.track_id join playlists as t3 on t2.playlist_id = t3.id where t3.name = 'Movies' intersect select t1.name from tracks as t1 join playlist_tracks as t2 on t1.id = t2.track_id join playlists as t3 on t2.playlist_id = t3.id where t3.name = 'Music'