题解 | 网易云音乐推荐(网易校招笔试真题)

select music_name
from follow f
join music_likes ml
on f.follower_id=ml.user_id
join music m
on m.id=ml.music_id
where 
    f.user_id=1 
    and 
    music_name not in(
        select music_name
        from follow f,music_likes ml,music m
        where f.user_id=ml.user_id and ml.music_id=m.id and f.user_id=1
    )
group by music_name,music_id
order by music_id