MySQL 时间戳（Timestamp）函数

1. 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 |

+---------------------+---------------------+

2. 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)

下面是示例：

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'

3. 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) --

请看示例部分：

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。