题解 | #网易云音乐推荐(网易校招笔试真题)#

SELECT
	music_name 
FROM
	music m
	where id in  (

	SELECT
		music_id 
	FROM
		music_likes 
	WHERE
		music_id NOT IN ( SELECT music_id FROM music_likes ml WHERE user_id = 1 ) 
		AND user_id IN ( SELECT follower_id AS nid FROM follow WHERE user_id = 1 ) 
	) order by m.id;
	
-- solute.2 
SELECT
	 music_name 
FROM
	music m
	inner JOIN (

	SELECT
		* 
	FROM
		music_likes 
	WHERE
		music_id NOT IN ( SELECT music_id FROM music_likes ml WHERE user_id = 1 ) 
		AND user_id IN ( SELECT follower_id AS nid FROM follow WHERE user_id = 1 ) 
	) y ON m.id = y.music_id;