题解 | #网易云音乐推荐(网易校招笔试真题)#

#1.获取id为1的用户所关注的用户信息

select user_id, follower_id from follow where user_id = 1;

#2.获取到所关注用户所喜欢的音乐数据

select music_id from music_likes where user_id in(select follower_id from follow where user_id = 1);

#3.排除当前用户所喜欢的音乐

select m.music_id from

(select music_id from music_likes where user_id in(select follower_id from follow where user_id = 1)) as m

where m.music_id not in(select music_id from music_likes where user_id = 1);

#4.向其推荐所关注用户喜欢的音乐

select music_name

from music

where id

in (select m.music_id from

(select music_id from music_likes where user_id in(select follower_id from follow where user_id = 1)) as m

where m.music_id not in(select music_id from music_likes where user_id = 1)) order by id;