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