快捷键多个Mysql SUMS在交织的日期范围内

Question

当我的网站上的用户登录时，会为统计信息执行多个查询。

SELECT SUM(earnings) FROM stats WHERE date BETWEEN $start_month AND $end_month 
SELECT SUM(earnings) FROM stats WHERE date BETWEEN $start_last_month AND $end_last_month 
SELECT SUM(earnings) FROM stats WHERE date BETWEEN $start_year AND NOW() 
//etc... 

我觉得我被要求它SUM所有这些对单独的查询“作弊” Mysql的引擎。例如，当它计算年收入时，它也在计算该月内的每月收入......但是，无论如何我都会再次查询它。

有没有更好的方法让多个日期范围交织的SUMS？

Answer 1

其实您可以使用CASE来计算earning。

SELECT SUM(CASE WHEN date BETWEEN $start_month AND $end_month THEN earnings ELSE 0 END), 
     SUM(CASE WHEN date BETWEEN $start_last_month AND $end_last_month THEN earnings ELSE 0 END), 
     SUM(CASE WHEN date BETWEEN $start_year AND NOW() THEN earnings ELSE 0 END) 
FROM stats