MySQL计算两个日期的相差天数

1.利用TO_DAYS函数

select to_days(now()) - to_days('20120512')

2.利用DATEDIFF函数

select datediff(now(),'20120512')

TIMESTAMPDIFF函数

可用于计算两日期时间之间相差的天数，秒数，分钟数，周数，小时数

语法：TIMESTAMPDIFF(unit,datetime_expr1,datetime_expr2)

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

-例如：

计算两日期之间相差多少秒

select timestampdiff(SECOND,'1997-10-12','2022-01-10');

计算两日期之间相差多少天

select timestampdiff(DAY,'1997-10-12','2022-01-10');

计算工龄

SELECT TIMESTAMPDIFF(YEAR,'2019-07-20',NOW()) AS 'working years';