#user_id=1的人关注的人喜欢的音乐
select music_name
from
(select distinct music_id, music_name
from music_likes
join music on music_id=id
where user_id in
(select follower_id
from follow
where user_id=1)
and music_id not in (select music_id from music_likes where user_id =1)
order by music_id)a

二刷 简单