select max(poster_id),account_id from poster group by account_id
SELECT p.poster_id,p.account_id FROM poster p WHERE NOT EXISTS (SELECT 1 FROM poster WHERE account_id=p.account_id AND update_time>p.update_time)
select a.poster_id ,a.accout_id,a.update_time from poster a, account b ,( select max(poster_id) as m_poster_id,account_id from poster group by account_id ) c where a.account_id = b.accout_id and accout_id =1 and a.poster_id=c.m_poster_id group by a.poster_id ,a.accout_id,a.update_time order by a.update_time desc limit 1
SELECT p1.poster_id,p1.account_id FROM poster p1, (SELECT account_id,max(update_time) ut FROM poster GROUP account_id) p2 WHERE p1.account_id=t2.account_id AND p1.update_time=p2.update_time ORDER BY p1.poster_id;
SELECT p1.poster_id,p1.account_id FROM poster p1, (SELECT account_id,max(update_time) ut FROM poster GROUP account_id) p2 WHERE p1.account_id=t2.account_id AND p1.update_time=p2.ut ORDER BY p1.poster_id;
from poster
group by account_id
SELECT p.poster_id,p.account_id
FROM poster p
WHERE NOT EXISTS
(SELECT 1 FROM poster WHERE account_id=p.account_id AND update_time>p.update_time)
from poster a, account b ,(
select max(poster_id) as m_poster_id,account_id
from poster
group by account_id
) c
where a.account_id = b.accout_id and accout_id =1
and a.poster_id=c.m_poster_id
group by a.poster_id ,a.accout_id,a.update_time
order by a.update_time desc limit 1
SELECT p1.poster_id,p1.account_id
FROM poster p1,
(SELECT account_id,max(update_time) ut
FROM poster
GROUP account_id) p2
WHERE p1.account_id=t2.account_id AND p1.update_time=p2.update_time
ORDER BY p1.poster_id;
SELECT p1.poster_id,p1.account_id
FROM poster p1,
(SELECT account_id,max(update_time) ut
FROM poster
GROUP account_id) p2
WHERE p1.account_id=t2.account_id AND p1.update_time=p2.ut
ORDER BY p1.poster_id;