题解 | #网易云音乐推荐(网易校招笔试真题)#

思路：

1. 连接三个表
2. 求出关注的人喜欢的音乐的id
3. 同时排除用户user_id = 1喜欢的音乐的id
4. 最后对music_id进行去重及对music.id进行排序

完整代码：

select distinct t3.music_name
from follow t1, music_likes t2, music t3
where t1.follower_id = t2.user_id
and t2.music_id = t3.id
and t1.user_id =1 
and t2.music_id not in (select music_id
						from music_likes
						where user_id =1)
order by t3.id