PHP / MySQL最新照片好友

Question

照片：id，uid，date;

朋友：uid1，uid2，日期，状态;

我想为用户的朋友展示最新照片。我该怎么办？

Answer 1

这样做：

SELECT p.id
FROM Photos AS p, Friends AS f
WHERE p.uid = f.uid2 AND f.uid1 = ${userX.id}
ORDER BY p.date DESC
LIMIT 1;

Answer 2

SELECT id FROM photos WHERE uid IN（SELECT uid2 FROM friends WHERE uid1 = {$ uid1} ORDER BY date DESC LIMIT 1）;

我认为UID1是用户而UID2是朋友，这将检索所有ID