MySQL TIMEDIFF() 返回两个时间之间的差值和时间总和

Question

我的查询是我想用 timediff 函数找到总和任何帮助

SELECT TIMEDIFF( timefrom, timeto )
FROM `leaveapply`
WHERE userid = '21'
GROUP BY leavetype
LIMIT 0 , 30

下面的语句将返回这样的时间

00:00:00
00:00:00
01:00:00
02:00:00

我想求和并得到结果，像这样03:00:00

Answer 1

尝试这样的事情:

select sum(
            SELECT TIMEDIFF( timefrom, timeto ) FROM `leaveapply`
            WHERE userid = '21'
            GROUP BY leavetype
          ) as total