MySQL TIMEDIFF() 返回两个时间和时间总和之间的差

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

以下语句将返回如下时间

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