Mysql计算时间差

SELECT TIMESTAMPDIFF(SECOND, now(), "-11-11 00:00:00")

语法为：TIMESTAMPDIFF(unit,datetime1,datetime2)，

其中unit单位有如下几种，分别是：FRAC_SECOND (microseconds), SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, QUARTER, or YEAR。