题解 | 网易云音乐推荐(网易校招笔试真题)

SELECT 
    music_name
FROM 
    (
        SELECT DISTINCT
            m.id,
            m.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 NOT EXISTS (
                SELECT 1
                FROM follow f2
                JOIN music_likes ml2 ON f2.user_id = ml2.user_id
                JOIN music m2 ON m2.id = ml2.music_id
                WHERE 
                    f2.user_id = 1
                    AND m2.music_name = m.music_name
            )
        ORDER BY 
            m.id
    ) t;