MySQL处理时间差问题

处理时间问题的函数很多，下面举例简单说几个常用的：

SELECT TIMESTAMPDIFF(YEAR,'2003-02-01','2005-05-01') AS 时间差（年）;
SELECT TIMESTAMPDIFF(MONTH,'2003-02-01','2003-05-01') AS 时间差（月）;
SELECT TIMESTAMPDIFF(DAY,'2003-02-01','2003-05-01') AS 时间差（日）;
SELECT TIMESTAMPDIFF(HOUR,'2003-02-01','2003-05-01') AS 时间差（小时）;
SELECT TIMESTAMPDIFF(MINUTE,'2003-02-01','2003-05-01') AS 时间差（分钟）;
SELECT TIMESTAMPDIFF(SECOND,'2003-02-01','2003-05-01') AS 时间差（秒）;

执行结果依次如下：

时间格式化

SELECT DATE_FORMAT('2003-02-01 13:05:30','%Y-%m-%d %H:%i:%S')
SELECT DATE_FORMAT(NOW(),'%Y-%m-%d %H:%i:%S')
SELECT DATE_FORMAT(CURDATE(),'%Y-%m-%d %H:%i:%S')

返回时间格式为：00:00:00

sec_to_time(sum(time_to_sec(sd.`endtime`)-time_to_sec(sd.`starttime`))) 持续时长,