只抓取phpbb中類別中所有主題的最後一篇文章

Question

我想只抓取單個查詢中phpbb數據庫中類別（Category-> Forum-> Topic-> Post）中所有主題的最後一篇文章。目前我已經熟悉了這一點，但它只返回第一個帖子，而不是最後一個。

SELECT *, MAX(p.post_id) 
FROM phpbb_forums f, phpbb_topics t, phpbb_posts p 
WHERE f.parent_id IN (<categories>) 
AND t.forum_id = f.forum_id 
AND p.topic_id = t.topic_id 
GROUP BY p.topic_id 

有誰知道如何正確地做到這一點？

Answer 1

SELECT * 
FROM phpbb_forums f 
JOIN phpbb_topics t 
ON  t.forum_id = f.forum_id 
JOIN phpbb_posts p 
ON  p.post_id = 
     (
     SELECT pi.post_id 
     FROM phpbb_posts pi 
     WHERE pi.topic_id = t.topic_id 
     ORDER BY 
       pi.date DESC 
     LIMIT 1 
     ) 
WHERE f.parent_id IN (…)