加快更新，内部加入，其中日期之间，MySQL组查询

Question

即时通讯运行下面的查询，并想知道是否有反正加快。

我每个月都会多次运行相同的查询，这很奇怪，因为有些月份运行速度非常快（10秒），有些运行时间很长（30分钟）。几个月之间的总和差异并不那么大，所以我不知道问题是什么。

下面是该查询

UPDATE appmonth a 
    INNER JOIN (SELECT activity_id, COUNT(*) AS counts FROM appmaster 
    WHERE upload_date BETWEEN '2014/05/01' AND '2014/05/31' 
    GROUP BY activity_id) b 
    on b.activity_id = a.activity_id 
SET `2014_05` = b.counts 

我没有在桌子上appmonth正在更新任何索引。

我对appmaster桌子下面的指标设置

• 活动，UPLOAD_DATE
• 活动
• UPLOAD_DATE，活动

Answer 1

我可以建议是这样的：

UPDATE appmonth AS a 
    INNER JOIN (SELECT activity_id, COUNT(*) AS counts FROM appmaster 
    WHERE upload_date >='2014/05/01' AND upload_date <= '2014/05/31' 
    GROUP BY activity_id) AS b 
    ON b.activity_id = a.activity_id 
SET a.`2014_05` = b.counts 

BETWE EN是一个缓慢的情况。

并在appmonth上添加索引'activity_id'。

P.S. appmaster上的索引'activity_id'是无用的，因为您还没有'activity_id，upload_date'