嗨,我有像贝娄这样的餐桌测试
viewtime event id
----------------------
10 end 101
290 prog 101
20 rew 101
我想要像end + prog-rew这样的输出,即(10 + 290-20)
输出将是:
viewtime event id
280 prog 101
最佳答案
一种解决方案是在以下情况下对SUM和CASE使用GROUP BY查询:
SELECT
id,
SUM(CASE WHEN event IN ('end', 'prog') THEN viewtime
WHEN event = 'rew' THEN -viewtime END) AS viewtime
FROM tablename
GROUP BY id
关于mysql - 如何在同一张表中添加两行并减去一行?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/34241762/