我在查询时遇到了一些困难:
SELECT d.*,
(SELECT COUNT(id) FROM downloads WHERE category = d.category) AS count
FROM downloads d
GROUP BY d.category
ORDER BY count DESC
因此,我试图获取每个类别的总下载次数,但每次运行此查询时都会挂起。
下载表有 +- 20000 行
我做错了什么?
最佳答案
SELECT category, count(id) as count
FROM downloads d
GROUP BY d.category
ORDER BY count DESC
关于mysql 慢 COUNT(),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3009635/