Mysql的时间函数

1.本周内的第几天，从周日开始
mysql> select dayofweek('2015-05-25');
+-------------------------+
| dayofweek('2015-05-25') |
+-------------------------+
|                       2 |
+-------------------------+
1 row in set (0.00 sec)

2.本月内的第几天
mysql> select dayofmonth('2015-05-25');
+--------------------------+
| dayofmonth('2015-05-25') |
+--------------------------+
|                       25 |
+--------------------------+
1 row in set (0.00 sec)

3.本年内的第几天
mysql> select dayofyear('2015-05-25');
+-------------------------+
| dayofyear('2015-05-25') |
+-------------------------+
|                     145 |
+-------------------------+
1 row in set (0.00 sec)

4.获取周几
mysql> select dayname('2015-05-26');
+-----------------------+
| dayname('2015-05-26') |
+-----------------------+
| Tuesday               |
+-----------------------+
1 row in set (0.04 sec)

5.获取月份
mysql> select month('2015-05-26'),monthname('2015-05-26');
+---------------------+-------------------------+
| month('2015-05-26') | monthname('2015-05-26') |
+---------------------+-------------------------+
|                   5 | May                     |
+---------------------+-------------------------+
1 row in set (0.00 sec)

6.获取第几周
mysql> select week('2015-05-26');
+--------------------+
| week('2015-05-26') |
+--------------------+
|                 21 |
+--------------------+
1 row in set (0.00 sec)

7.获取第几季度
mysql> select quarter('2015-06-26');
+-----------------------+
| quarter('2015-06-26') |
+-----------------------+
|                     2 |
+-----------------------+
1 row in set (0.00 sec)

8.查看年份
mysql> select year('2015-09-26');
+--------------------+
| year('2015-09-26') |
+--------------------+
|               2015 |
+--------------------+
1 row in set (0.00 sec)

9.其他
mysql> select year('2015-05-26'),month('2015-05-26'),day('2015-05-26');
+--------------------+---------------------+-------------------+
| year('2015-05-26') | month('2015-05-26') | day('2015-05-26') |
+--------------------+---------------------+-------------------+
|               2015 |                   5 |                26 |
+--------------------+---------------------+-------------------+
1 row in set (0.01 sec)

mysql> select hour('10:05:03'),minute('10:05:03'),second('10:05:03');
+------------------+--------------------+--------------------+
| hour('10:05:03') | minute('10:05:03') | second('10:05:03') |
+------------------+--------------------+--------------------+
|               10 |                  5 |                  3 |
+------------------+--------------------+--------------------+
1 row in set (0.00 sec)

10.查看当前时间
mysql> select current_time(),sysdate(),current_timestamp(),now();
+----------------+---------------------+---------------------+---------------------+
| current_time() | sysdate()           | current_timestamp() | now()               |
+----------------+---------------------+---------------------+---------------------+
| 00:29:05       | 2015-05-26 00:29:05 | 2015-05-26 00:29:05 | 2015-05-26 00:29:05 |
+----------------+---------------------+---------------------+---------------------+
1 row in set (0.00 sec)

其他类似内置函数，now是跟session有关的，sysdate无关事务
current_timestamp(),
current_timestamp,
localtime(),
localtime,
localtimestamp,
localtimestamp()

11.unix时间戳转换
mysql> select unix_timestamp('2015-05-26 15:38:22'),unix_timestamp(now());
+---------------------------------------+-----------------------+
| unix_timestamp('2015-05-26 15:38:22') | unix_timestamp(now()) |
+---------------------------------------+-----------------------+
|                            1432679902 |            1432625945 |
+---------------------------------------+-----------------------+
1 row in set (0.00 sec)

mysql> select from_unixtime(1432679902),from_unixtime(1432625945);
+---------------------------+---------------------------+
| from_unixtime(1432679902) | from_unixtime(1432625945) |
+---------------------------+---------------------------+
| 2015-05-26 15:38:22       | 2015-05-26 00:39:05       |
+---------------------------+---------------------------+
1 row in set (0.00 sec)

12.format格式
%M 月名字(January……December)
%W 星期名字(Sunday……Saturday)
%D 有英语前缀的月份的日期(1st, 2nd, 3rd, 等等。）
%Y 年, 数字, 4 位
%y 年, 数字, 2 位
%a 缩写的星期名字(Sun……Sat)
%d 月份中的天数, 数字(00……31)
%e 月份中的天数, 数字(0……31)
%m 月, 数字(01……12)
%c 月, 数字(1……12)
%b 缩写的月份名字(Jan……Dec)
%j 一年中的天数(001……366)
%H 小时(00……23)
%k 小时(0……23)
%h 小时(01……12)
%I 小时(01……12)
%l 小时(1……12)
%i 分钟, 数字(00……59)
%r 时间,12 小时(hh:mm:ss [AP]M)
%T 时间,24 小时(hh:mm:ss)
%S 秒(00……59)
%s 秒(00……59)
%p AM或PM
%w 一个星期中的天数(0=Sunday ……6=Saturday ）
%U 星期(0……52), 这里星期天是星期的第一天
%u 星期(0……52), 这里星期一是星期的第一天
%% 字符%

mysql>  select now(),DATE_FORMAT(now(),'%M %D %Y %b %a %d %e %j %i');
+---------------------+-------------------------------------------------+
| now()               | DATE_FORMAT(now(),'%M %D %Y %b %a %d %e %j %i') |
+---------------------+-------------------------------------------------+
| 2015-05-26 01:38:17 | May 26th 2015 May Tue 26 26 146 38              |
+---------------------+-------------------------------------------------+
1 row in set (0.00 sec)

13.时间运算
mysql> select now(),date_add(now(),interval 11 second);
+---------------------+------------------------------------+
| now()               | date_add(now(),interval 11 second) |
+---------------------+------------------------------------+
| 2015-05-27 00:22:20 | 2015-05-27 00:22:31                |
+---------------------+------------------------------------+
1 row in set (0.00 sec)

mysql> select now(),date_add(now(),interval 1 hour);
+---------------------+---------------------------------+
| now()               | date_add(now(),interval 1 hour) |
+---------------------+---------------------------------+
| 2015-05-27 00:23:26 | 2015-05-27 01:23:26             |
+---------------------+---------------------------------+
1 row in set (0.00 sec)

mysql> select now(),date_add(now(),interval 1 day);
+---------------------+--------------------------------+
| now()               | date_add(now(),interval 1 day) |
+---------------------+--------------------------------+
| 2015-05-27 00:22:28 | 2015-05-28 00:22:28            |
+---------------------+--------------------------------+
1 row in set (0.00 sec)

mysql> select now(),date_add(now(),interval 1 month);
+---------------------+----------------------------------+
| now()               | date_add(now(),interval 1 month) |
+---------------------+----------------------------------+
| 2015-05-27 00:23:57 | 2015-06-27 00:23:57              |
+---------------------+----------------------------------+
1 row in set (0.00 sec)

mysql> select now(),date_add(now(),interval -1 year);
+---------------------+----------------------------------+
| now()               | date_add(now(),interval -1 year) |
+---------------------+----------------------------------+
| 2015-05-27 00:24:34 | 2014-05-27 00:24:34              |
+---------------------+----------------------------------+
1 row in set (0.06 sec)