我们的一个网站有一个约60'000条记录的表格。最近我们注意到页面超时,只能通过将内存限制设置为-1来解决。这允许页面加载,但速度很慢。此外,我不相信这是解决问题的正确方法,显然这表明事情并不完全正确。MySQL子查询选择速度很慢
我到输出管理的查询页面正在运行:我在phpMyAdmin跑到这个查询
SELECT u.*,
(SELECT COUNT(*) FROM enquiry e WHERE e.user_id = u.id AND e.deleted = 0 AND e.time_started != 0) AS opened_count,
(SELECT COUNT(*) FROM enquiry e WHERE e.user_id = u.id AND e.deleted = 0 AND e.confirmed = 1 AND e.time_started != 0) AS confirmed_count,
(SELECT COUNT(*) FROM enquiry e WHERE e.user_id = u.id AND e.deleted = 0 AND e.call_back = 1 AND e.time_started != 0) AS call_back_count
FROM user u
WHERE u.active = 1 AND u.deleted = 0
ORDER BY u.username
,并接管30秒返回结果。
我觉得查询需要以某种方式优化,但我正在努力研究如何。我猜我需要使用某种JOIN?
请提供'EXPLAIN'和'DESCRIBE'结果。 – Kermit