sql时间函数

1、adddate—将时间/日期间隔添加到日期

adddate("2015-01-03",INTERVAL 1 day) #2015-01-04

2、date_add,date_sub—增加/减去指定的时间间隔

date_add("2025-02-27",interval 1 day) #2025-02-28
date_sub("2025-02-27",interval 1 day) #2025-02-26

3、datediff—返回值是相差的天数

DATEDIFF('2025-02-27','2025-02-26');   # 1
DATEDIFF('2025-02-26','2025-02-27');   # -1

4、TIMESTAMPDIFF

#计算相差天数：
select TIMESTAMPDIFF(DAY,'2019-05-20', '2019-05-21'); # 1

#计算相差小时数：
select TIMESTAMPDIFF(HOUR, '2015-03-22 07:00:00', '2015-03-22 18:00:00'); # 11

#计算相差秒数：
select TIMESTAMPDIFF(SECOND, '2015-03-22 07:00:00', '2015-03-22 7:01:01'); # 61

5、interval

"2015-01-03"+interval'1' day #2015-01-04