SELECT s.song_name, a.artist_name, al.album_name
FROM artist a
LEFT JOIN song_artist sa ON sa.artist_id = a.id
LEFT JOIN song s ON s.id = sa.song_id
LEFT JOIN album al ON al.id = s.album_id
JOIN の詳細
SELECT s.song_name, a.artist_name, al.album_name
FROM artist a
LEFT JOIN song_artist sa ON sa.artist_id = a.id
LEFT JOIN song s ON s.id = sa.song_id
LEFT JOIN album al ON al.id = s.album_id
JOIN の詳細