编程语言：SQL
一个用户SQL慢查询分析，原因及优化
问题描述 一个用户反映线上一个SQL语句执行时间慢得无法接受。SQL语句看上去很简单（本文描述中修改了表名和字段名): SELECT count(*) FROM a JOIN b ON a.S = b.S WHERE a.L > '2014-03-30 00:55:00' AND a.L < '2014-03-30 01:00:00' ; 且查询需要的字段都建了索引，表结构如下：…
动态 SQL
File not found The site configured at this address does not contain the requested file. If this is your site, make sure that the filename case matches the URL as well as any file permissions. For root…