题解 | #网易云音乐推荐(网易校招笔试真题)#

# select
# distinct m.music_name
# from
# (
# select music_id
# from music_likes
# 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)
# ) a 
# join music as m on a.music_id = m.id
# order by m.id

select
music_name
from music
where id in 
(
    select music_id from music_likes where user_id in 
    (select follower_id from follow where user_id=1)
)
and id not in 
(
    select music_id from music_likes where user_id=1
)
order by id