mysql - 如何合并来自同一个表的两个sql查询

Question

我在表格中有以下(示例)数据

值、日期、设备

我使用这些数据进行简单的 SLA 计算，即在工作时间内数据低于特定阈值的次数。

目前我运行如下两个查询

select count(*), DATE(times) from SLA where device='some-dev' and DATE(times) between '2013-05-01' and '2013-05-31' and TIME(times) between '06:00:00' and '18:00:00' and value <150 group by DATE(times);

select count(*), DATE(times) from SLA where device='some-dev' and DATE(times) between '2013-05-01' and '2013-05-31' and TIME(times) between '06:00:00' and '18:00:00' group by DATE(times);

所以有两个查询，一个没有值 < 数字，一个有。

有几个问题，有没有一种方法可以将这两者都放入一个查询中，这样我就可以看到总数据点和小于阈值的数据点的计数？基本上返回三列，一列有计数，一列计数低于阈值，还有日期

除此之外，有没有简单的方法告诉 mysql 在返回数据时忽略周末？

谢谢，

Answer 1

使用 UNION 运算符。

更新后的查询如下所示:

(select count(*), DATE(times) from SLA where device='some-dev' and DATE(times) between '2013-05-01' and '2013-05-31' and TIME(times) between '06:00:00' and '18:00:00' and value <150 group by DATE(times))
UNION
(select count(*), DATE(times) from SLA where device='some-dev' and DATE(times) between '2013-05-01' and '2013-05-31' and TIME(times) between '06:00:00' and '18:00:00' group by DATE(times));