题解 | #网易云音乐推荐(网易校招笔试真题)#

思路：①找出user_id=1的人关注者的音乐id，音乐名,形成tb2；②在tb2里剔除user_id=1已经有的音乐即可。

with tb2 as(
    select music_id, music_name from music_likes left join music on music_likes.music_id=music.id
    where user_id in (select follower_id from follow where user_id=1))

select music_name from tb2 
where music_name not in (select music_name from music_likes left join music on music_likes.music_id=music.id where user_id=1)
group by music_id, music_name
order by music_id