#两日期/时间之间相差的天数：
To_Days(end_time)-To_Days(start_time) #两日期/时间之间相差的秒数： SELECT UNIX_TIMESTAMP(end_time)- UNIX_TIMESTAMP(start_time); #两日期/时间之间相差的时分数： SELECT SEC_TO_TIME(UNIX_TIMESTAMP(end_time)- UNIX_TIMESTAMP(start_time));最好的办法是直接用“+”，“-” 计算，目前的版本都支持了。比如：SELECT * FROM Table_Name WHERE loginDate < NOW() -10 * 60;实例：
SELECT SEC_TO_TIME(UNIX_TIMESTAMP((SELECT createdtime FROM `Z_2015-09-15` WHERE deviceid='460040271516782' order by id DESC limit 1)) - UNIX_TIMESTAMP((SELECT createdtime FROM `Z_2015-09-15` WHERE deviceid='460040271516782' limit 1)));