ＭySQL日期时间函数大全
1.获取当前时间+日期 函数now()
mysql> select now(); +---------------------+ | now() | +---------------------+ | 2008-08-08 22:20:46 | +---------------------+
获得当前日期+时间（date + time）函数：sysdate()
sysdate() 日期时间函数跟 now() 类似，不同之处在于：now() 在执行开始时值就得到了， sysdate() 在函数执行时动态得到值。看下面的例子就明白了：
mysql> select now(), sleep(3), now(); +---------------------+----------+---------------------+ | now() | sleep(3) | now() | +---------------------+----------+---------------------+ | 2008-08-08 22:28:21 | 0 | 2008-08-08 22:28:21 | +---------------------+----------+---------------------+
MySQL 获得当前时间戳函数：current_timestamp, current_timestamp()
mysql> select current_timestamp, current_timestamp(); +---------------------+---------------------+ | current_timestamp | current_timestamp() | +---------------------+---------------------+ | 2008-08-09 23:22:24 | 2008-08-09 23:22:24 | +---------------------+---------------------+
MySQL 日期转换函数、时间转换函数
MySQL Date/Time to Str（日期/时间转换为字符串）函数：date_format(date,format), time_format(time,format)
mysql> select date_format('2008-08-08 22:23:01', '%Y%m%d%H%i%s'); +----------------------------------------------------+ | date_format('2008-08-08 22:23:01', '%Y%m%d%H%i%s') | +----------------------------------------------------+ | 20080808222301 | +----------------------------------------------------+
可以看到，str_to_date(str,format) 转换函数，可以把一些杂乱无章的字符串转换为日期格式。另外，它也可以转换为时间。“format” 可以参看 MySQL 手册。
MySQL （日期、天数）转换函数：to_days(date), from_days(days)
select to_days('0000-00-00'); -- 0 select to_days('2008-08-08'); -- 733627
MySQL （时间、秒）转换函数：time_to_sec(time), sec_to_time(seconds)
select time_to_sec('01:00:05'); -- 3605 select sec_to_time(3605); -- '01:00:05'
MySQL 拼凑日期、时间函数：makdedate(year,dayofyear), maketime(hour,minute,second)
select makedate(2001,31); -- '2001-01-31' select makedate(2001,32); -- '2001-02-01' select maketime(12,15,30); -- '12:15:30'
MySQL （Unix 时间戳、日期）转换函数
unix_timestamp(),
unix_timestamp(date),
from_unixtime(unix_timestamp),
from_unixtime(unix_timestamp,format)
select unix_timestamp(); -- 1218290027 select unix_timestamp('2008-08-08'); -- 1218124800 select unix_timestamp('2008-08-08 12:30:00'); -- 1218169800 select from_unixtime(1218290027); -- '2008-08-09 21:53:47' select from_unixtime(1218124800); -- '2008-08-08 00:00:00' select from_unixtime(1218169800); -- '2008-08-08 12:30:00' select from_unixtime(1218169800, '%Y %D %M %h:%i:%s %x'); -- '2008 8th August 12:30:00 2008'
MySQL 日期时间计算函数
MySQL 为日期增加一个时间间隔：date_add()
set @dt = now(); select date_add(@dt, interval 1 day); -- add 1 day select date_add(@dt, interval 1 hour); -- add 1 hour select date_add(@dt, interval 1 minute); -- ... select date_add(@dt, interval 1 second); select date_add(@dt, interval 1 microsecond); select date_add(@dt, interval 1 week); select date_add(@dt, interval 1 month); select date_add(@dt, interval 1 quarter); select date_add(@dt, interval 1 year); select date_add(@dt, interval -1 day); -- sub 1 day
MySQL adddate(), addtime()函数，可以用 date_add() 来替代。下面是 date_add() 实现 addtime() 功能示例：
mysql> set @dt = '2008-08-09 12:12:33'; mysql> mysql> select date_add(@dt, interval '01:15:30' hour_second); +------------------------------------------------+ | date_add(@dt, interval '01:15:30' hour_second) | +------------------------------------------------+ | 2008-08-09 13:28:03 | +------------------------------------------------+ mysql> select date_add(@dt, interval '1 01:15:30' day_second); +-------------------------------------------------+ | date_add(@dt, interval '1 01:15:30' day_second) | +-------------------------------------------------+ | 2008-08-10 13:28:03 | +-------------------------------------------------+
MySQL 为日期减去一个时间间隔：date_sub()
mysql> select date_sub('1998-01-01 00:00:00', interval '1 1:1:1' day_second); +----------------------------------------------------------------+ | date_sub('1998-01-01 00:00:00', interval '1 1:1:1' day_second) | +----------------------------------------------------------------+ | 1997-12-30 22:58:59 | +----------------------------------------------------------------+
MySQL date_sub() 日期时间函数 和 date_add() 用法一致，不再赘述。
MySQL 日期、时间相减函数：datediff(date1,date2), timediff(time1,time2)
MySQL datediff(date1,date2)：两个日期相减 date1 - date2，返回天数。 select datediff('2008-08-08', '2008-08-01'); -- 7 select datediff('2008-08-01', '2008-08-08'); -- -7
MySQL timediff(time1,time2)：两个日期相减 time1 - time2，返回 time 差值。
select timediff('2008-08-08 08:08:08', '2008-08-08 00:00:00'); -- 08:08:08 select timediff('08:08:08', '00:00:00'); -- 08:08:08
注意：timediff(time1,time2) 函数的两个参数类型必须相同。
MySQL 时间戳（timestamp）转换、增、减函数：
timestamp(date) -- date to timestamp timestamp(dt,time) -- dt + time timestampadd(unit,interval,datetime_expr) -- timestampdiff(unit,datetime_expr1,datetime_expr2) --
select timestamp('2008-08-08'); -- 2008-08-08 00:00:00 select timestamp('2008-08-08 08:00:00', '01:01:01'); -- 2008-08-08 09:01:01 select timestamp('2008-08-08 08:00:00', '10 01:01:01'); -- 2008-08-18 09:01:01 select timestampadd(day, 1, '2008-08-08 08:00:00'); -- 2008-08-09 08:00:00 select date_add('2008-08-08 08:00:00', interval 1 day); -- 2008-08-09 08:00:00 MySQL timestampadd() 函数类似于 date_add()。 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 select datediff('2008-08-08 12:00:00', '2008-08-01 00:00:00'); -- 7
MySQL timestampdiff() 函数就比 datediff() 功能强多了，datediff() 只能计算两个日期（date）之间相差的天数。
MySQL 时区（timezone）转换函数
convert_tz(dt,from_tz,to_tz) select convert_tz('2008-08-08 12:00:00', '+08:00', '+00:00'); -- 2008-08-08 04:00:00 时区转换也可以通过 date_add, date_sub, timestampadd 来实现。 select date_add('2008-08-08 12:00:00', interval -8 hour); -- 2008-08-08 04:00:00 select date_sub('2008-08-08 12:00:00', interval 8 hour); -- 2008-08-08 04:00:00 select timestampadd(hour, -8, '2008-08-08 12:00:00'); -- 2008-08-08 04:00:00
