How to get record with max id?

Question

PHP

table posts

id  link    user_id
22 www   44
23  ddd    44
33  ddd    55

Table comments

id   user_id, some_id
2     44           66
3     55           66

Have a request

SELECT posts.id,  posts.link, posts.user_id FROM posts WHERE posts.user_id IN (SELECT comments.user_id FROM comments WHERE some.id=66)  GROUP BY posts.user_id

Result
post.id posts.link, posts.user_id
22 www.az.ru 44
50 www.me.ru 55 As a
result, I get what I need, but the user has a lot of posts, how to get exactly the last added post.

Answer 1

SELECT posts.id,  posts.link, posts.user_id FROM posts WHERE posts.user_id IN (SELECT comments.user_id FROM comments WHERE some.id=66)  WHERE MAX(post.id)

In general, if you need to get exactly the "last added post", then it's better to add a timestamp column and choose MAX(timestamp). After all, the "last" criterion implies a check by the time of adding IMHO.