语法如下： timestampdiff(unit,datetime_expr1,datetime_expr2) --
示例：
select timestampdiff(year,'2002-05-01','2001-01-01'); -- -1 select timestampdiff(day ,'2002-05-01','2001-01-01'); -- -485 select timestampdiff(hour,'2008-08-08 12:00:00','2008-08-08 00:00:00'); -- -12
总结：
MySQL timestampdiff() 函数比 datediff() 功能强多了，datediff() 只能计算两个日期（date）之间相差的天数。