复杂的选择查询

Question

SELECT *, IF(start_date < ".$twoDaysAgo.", (posts / 172800 * 50000), (posts / (".$curTime." - start_date) * 50000)) as rating 
FROM 
(
    SELECT t1.*, t2.*, count(t2.id) as posts 
    FROM topics as t1 
    LEFT JOIN 
    (
        SELECT id, topic_id as tid, poster, body, post_date, poster_ip, subject 
        FROM messages t9
    ) as t2 
    ON t1.topic_id = t2.tid 
    GROUP BY t1.topic_id
) as t3 
ORDER BY rating DESC, topic_id ASC

posts列提供了主题的alltime-postcounts。没关系，我想要那个。但我还想在过去两天内获得主题的帖子。换句话说，我需要在一个查询中获取主题'alltime-postcounts和2-day-postcounts。

表主题： topics http://easycaptures.com/fs/uploaded/802/8788454634.png

表消息： messages http://easycaptures.com/fs/uploaded/802/8788454634.png

Answer 1

这样的事情会起作用：

SELECT count(*) AS all_time, SUM(start_date > $twoDaysAgo) AS last_2_days

MySQL会将start_date比较布尔值自动转换为整数0或1，然后总结那些1，有效地为您提供所需的计数。