mysql常用日期时间/数值函数

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mysql常用日期时间/数值函数

来源: 作者: 时间:2016-02-21 09:46 【

mysql常用日期时间/数值函数1.日期时间函数时间转化秒函数:time_to_secmysql select time_to_sec(#39;01:01:01#39;);+-------------------------+| time_to_sec(#39;01:01:01#39;) |+-----------------...
常用日期时间/数值函数
 
1.日期时间函数
 
时间转化秒函数:time_to_sec
mysql> select time_to_sec('01:01:01');
+-------------------------+
| time_to_sec('01:01:01') |
+-------------------------+
|                    3661 | 
+-------------------------+
1 row in set (0.00 sec)
 
秒转化时间函数:sec_to_time
mysql> select sec_to_time(3661);
+-------------------+
| sec_to_time(3661) |
+-------------------+
| 01:01:01          | 
+-------------------+
1 row in set (0.00 sec)
 
日期转为天数函数:to_days
mysql> select to_days('0000-00-00');
+-----------------------+
| to_days('0000-00-00') |
+-----------------------+
|                  NULL | 
+-----------------------+
1 row in set, 1 warning (0.01 sec)
mysql> select to_days('0001-01-01');
+-----------------------+
| to_days('0001-01-01') |
+-----------------------+
|                   366 | 
+-----------------------+
1 row in set (0.00 sec)
 
天数转化日期函数:from_days
mysql> select from_days(0);
+--------------+
| from_days(0) |
+--------------+
| 0000-00-00   | 
+--------------+
1 row in set (0.00 sec)
mysql> select from_days(366);
+----------------+
| from_days(366) |
+----------------+
| 0001-01-01     | 
+----------------+
1 row in set (0.00 sec)
 
字符串转换为日期函数:str_to_date
mysql> select str_to_date('2013-01-01 01:21:01','%Y-%m-%d %H:%i:%s');
+--------------------------------------------------------+
| str_to_date('2013-01-01 01:21:01','%Y-%m-%d %H:%i:%s') |
+--------------------------------------------------------+
| 2013-01-01 01:21:01                                    | 
+--------------------------------------------------------+
1 row in set (0.00 sec)
 
日期转换为字符串函数:date_format
mysql> select date_format('2013-01-01 01:21:01','%Y%m%d %H%i%s');
+----------------------------------------------------+
| date_format('2013-01-01 01:21:01','%Y%m%d %H%i%s') |
+----------------------------------------------------+
| 20130101 012101                                    | 
+----------------------------------------------------+
1 row in set (0.00 sec)
 
时间转换为字符串函数:time_format
mysql> select time_format('01:21:01','%H%i%s');
+----------------------------------+
| time_format('01:21:01','%H%i%s') |
+----------------------------------+
| 012101                           | 
+----------------------------------+
1 row in set (0.00 sec)
 
说明:
日期时间格式参数如下:
%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 
%% 一个文字“%”。
 
提取表达式的日期部分
mysql> select date(now());
+-------------+
| date(now()) |
+-------------+
| 2013-05-16  | 
+-------------+
1 row in set (0.00 sec)
 
返回表达式的星期索引(0=星期一,1=星期二, ……6= 星期天)。
mysql> select weekday(now());
+----------------+
| weekday(now()) |
+----------------+
|              3 | 
+----------------+
1 row in set (0.00 sec)
 
返回表达式是一年的第几周
mysql> select week(now());
+-------------+
| week(now()) |
+-------------+
|          19 | 
+-------------+
1 row in set (0.00 sec)
 
WEEK()允许指定星期是否开始于星期天或星期一。如果第二个参数是0,星期从星期天开始,如果第二个参数是1, 从星期一开始,如下所示:
mysql> select week(now(),0);
+---------------+
| week(now(),0) |
+---------------+
|            19 | 
+---------------+
1 row in set (0.00 sec)
mysql> select week(now(),1);
+---------------+
| week(now(),1) |
+---------------+
|            20 | 
+---------------+
1 row in set (0.00 sec)
 
返回表达式一年中季度
mysql> select quarter(now());
+----------------+
| quarter(now()) |
+----------------+
|              2 | 
+----------------+
1 row in set (0.00 sec)
 
返回表达式一周的第一天
mysql> select dayofweek(now());
+------------------+
| dayofweek(now()) |
+------------------+
|                5 | 
+------------------+
1 row in set (0.00 sec)
 
返回表达式一个月的第几天
mysql> select dayofmonth(now());
+-------------------+
| dayofmonth(now()) |
+-------------------+
|                16 | 
+-------------------+
1 row in set (0.00 sec)
 
返回表达式一年的第几天
mysql> select dayofyear(now());
+------------------+
| dayofyear(now()) |
+------------------+
|              136 | 
+------------------+
1 row in set (0.00 sec)
 
返回表达式的星期名字
mysql> select dayname(now());
+----------------+
| dayname(now()) |
+----------------+
| Thursday       | 
+----------------+
1 row in set (0.00 sec)
 
返回表达式月份的名字
mysql> select monthname(now());
+------------------+
| monthname(now()) |
+------------------+
| May              | 
+------------------+
1 row in set (0.00 sec)
mysql>
 
提取表达式的年份
mysql> select year(now());
+-------------+
| year(now()) |
+-------------+
|        2013 | 
+-------------+
1 row in set (0.00 sec)
 
提取表达式的月份
mysql> select month(now());
+--------------+
| month(now()) |
+--------------+
|            5 | 
+--------------+
1 row in set (0.01 sec)
 
提取表达式的天数
mysql> select day(now());
+------------+
| day(now()) |
+------------+
|         16 | 
+------------+
1 row in set (0.00 sec)
 
提取表达式的小时
mysql> select hour(now());
+-------------+
| hour(now()) |
+-------------+
|          16 | 
+-------------+
1 row in set (0.00 sec)
 
提取表达式的分钟
mysql> select minute(now());
+---------------+
| minute(now()) |
+---------------+
|            31 | 
+---------------+
1 row in set (0.00 sec)
 
提取表达式的秒数
mysql> select second(now());
+---------------+
| second(now()) |
+---------------+
|            34 | 
+---------------+
1 row in set (0.00 sec)
 
将当前日期按照'YYYY-MM-DD' 或YYYYMMDD 格式的值返回,具体格式根据函数用在字符串或是数字语境中而定。
mysql> select curdate();
+------------+
| curdate()  |
+------------+
| 2013-05-16 | 
+------------+
1 row in set (0.00 sec)
mysql> select curdate()+1;
+-------------+
| curdate()+1 |
+-------------+
|    20130517 | 
+-------------+
1 row in set (0.00 sec)
 
将当前时间以'HH:MM:SS'或 HHMMSS的格式返回,具体格式根据函数用在字符串或是数字语境中而定。 
mysql> select curtime();
+-----------+
| curtime() |
+-----------+
| 16:43:10  | 
+-----------+
1 row in set (0.00 sec)
mysql> select curtime()+1;
+---------------+
| curtime()+1   |
+---------------+
| 164420.000000 | 
+---------------+
1 row in set (0.00 sec)
 
获取当前日期时间:sysdate(),now()
mysql> select sysdate(),sleep(2),sysdate();
+---------------------+----------+---------------------+
| sysdate()           | sleep(2) | sysdate()           |
+---------------------+----------+---------------------+
| 2013-05-16 17:16:04 |        0 | 2013-05-16 17:16:06 | 
+---------------------+----------+---------------------+
1 row in set (2.00 sec)
mysql> select now(),sleep(2),now();
+---------------------+----------+---------------------+
| now()               | sleep(2) | now()               |
+---------------------+----------+---------------------+
| 2013-05-16 17:16:18 |        0 | 2013-05-16 17:16:18 | 
+---------------------+----------+---------------------+
1 row in set (2.00 sec)
从上面可以看到sysdate和now的区别,now表示语句开始的时间,而sysdate实时的获取时间
 
 
将当前日期按照'YYYY-MM-DD HH:MM:SS'或YYYYMMDDHHMMSS格式的值返回,具体格式根据函数用在字符串或是数字语境中而定。
mysql> select current_timestamp;
+---------------------+
| current_timestamp   |
+---------------------+
| 2013-05-16 17:19:51 | 
+---------------------+
1 row in set (0.00 sec)
mysql> select current_timestamp+1;
+-----------------------+
| current_timestamp+1   |
+-----------------------+
| 20130516172008.000000 | 
+-----------------------+
1 row in set (0.00 sec)
 
unix_timestamp(),unix_timestamp(date)
如果没有参数调用,返回一个Unix时间戳记(从'1970-01-01 00:00:00'GMT开始的秒数)。如果UNIX_TIMESTAMP()用一 
个date参数被调用,它返回从'1970-01-01 00:00:00' GMT开始的秒数值。date可以是一个DATE字符串、一个DATETIME 
字符串、一个TIMESTAMP或以YYMMDD或YYYYMMDD格式的本地时间的一个数字。 
mysql> select unix_timestamp();
+------------------+
| unix_timestamp() |
+------------------+
|       1368696216 | 
+------------------+
1 row in set (0.00 sec)
mysql> select unix_timestamp('2013-05-16 01:01:01');
+---------------------------------------+
| unix_timestamp('2013-05-16 01:01:01') |
+---------------------------------------+
|                            1368637261 | 
+---------------------------------------+
1 row in set (0.00 sec)
mysql>
 
FROM_UNIXTIME(unix_timestamp) 
以'YYYY-MM-DD HH:MM:SS'或YYYYMMDDHHMMSS格式返回unix_timestamp参数所表示的值,具体格式根据函数用在字符串或是数字语境中而定
mysql> select from_unixtime(1368637261);
+---------------------------+
| from_unixtime(1368637261) |
+---------------------------+
| 2013-05-16 01:01:01       | 
+---------------------------+
1 row in set (0.00 sec)
mysql> select from_unixtime(1368637261)+1;
+-----------------------------+
| from_unixtime(1368637261)+1 |
+-----------------------------+
|       20130516010102.000000 | 
+-----------------------------+
1 row in set (0.00 sec)
mysql> select from_unixtime(1368637261,'%Y-%m-%d %h:%i:%s');
+-----------------------------------------------+
| from_unixtime(1368637261,'%Y-%m-%d %h:%i:%s') |
+-----------------------------------------------+
| 2013-05-16 01:01:01                           | 
+-----------------------------------------------+
1 row in set (0.00 sec)
 
返回表达式所在月的最后一天
mysql> select last_day(now());
+-----------------+
| last_day(now()) |
+-----------------+
| 2013-05-31      | 
+-----------------+
1 row in set (0.00 sec)
 
日期加减运算
DATE_ADD(date,INTERVAL expr type) --加法
DATE_SUB(date,INTERVAL expr type) --减法
 
mysql> select date_add('2013-05-16 01:01:01',interval 1 second);
+---------------------------------------------------+
| date_add('2013-05-16 01:01:01',interval 1 second) |
+---------------------------------------------------+
| 2013-05-16 01:01:02                               | 
+---------------------------------------------------+
1 row in set (0.00 sec)
 
mysql> select date_add('2013-05-16 01:01:01',interval 1 day);
+------------------------------------------------+
| date_add('2013-05-16 01:01:01',interval 1 day) |
+------------------------------------------------+
| 2013-05-17 01:01:01                            | 
+------------------------------------------------+
1 row in set (0.00 sec)
 
mysql> select date_add('2013-05-16 01:01:01',interval 1 minute);
+---------------------------------------------------+
| date_add('2013-05-16 01:01:01',interval 1 minute) |
+---------------------------------------------------+
| 2013-05-16 01:02:01                               | 
+---------------------------------------------------+
1 row in set (0.00 sec)
 
mysql> select date_add('2013-05-16 01:01:01',interval 1 hour);
+-------------------------------------------------+
| date_add('2013-05-16 01:01:01',interval 1 hour) |
+-------------------------------------------------+
| 2013-05-16 02:01:01                             | 
+-------------------------------------------------+
1 row in set (0.00 sec)
 
mysql> select date_add('2013-05-16 01:01:01',interval '1:1' minute_second);
+--------------------------------------------------------------+
| date_add('2013-05-16 01:01:01',interval '1:1' minute_second) |
+--------------------------------------------------------------+
| 2013-05-16 01:02:02                                          | 
+--------------------------------------------------------------+
1 row in set (0.00 sec)
 
mysql> select date_add('2013-05-16 01:01:01', interval '1 1:1:1' day_second);
+----------------------------------------------------------------+
| date_add('2013-05-16 01:01:01', interval '1 1:1:1' day_second) |
+----------------------------------------------------------------+
| 2013-05-17 02:02:02                                            | 
+----------------------------------------------------------------+
1 row in set (0.00 sec)
 
type值格式: 
SECOND 秒 SECONDS 
MINUTE 分钟 MINUTES 
HOUR 时间 HOURS 
DAY 天 DAYS 
MONTH 月 MONTHS 
YEAR 年 YEARS 
MINUTE_SECOND 分钟和秒 "MINUTES:SECONDS" 
HOUR_MINUTE 小时和分钟 "HOURS:MINUTES" 
DAY_HOUR 天和小时 "DAYS HOURS" 
YEAR_MONTH 年和月 "YEARS-MONTHS" 
HOUR_SECOND 小时, 分钟, "HOURS:MINUTES:SECONDS" 
DAY_MINUTE 天, 小时, 分钟 "DAYS HOURS:MINUTES" 
DAY_SECOND 天, 小时, 分钟, 秒 "DAYS HOURS:MINUTES:SECONDS"
 
DATEDIFF(expr, expr2)
返回起始时间 expr和结束时间expr2之间的天数。Expr和expr2为日期或 date-and-time 表达式。计算中只用到这些值的日期部分。
mysql> select datediff('2013-05-16 06:01:01', '2013-05-17 01:01:01');
+--------------------------------------------------------+
| datediff('2013-05-16 06:01:01', '2013-05-17 01:01:01') |
+--------------------------------------------------------+
|                                                     -1 | 
+--------------------------------------------------------+
1 row in set (0.00 sec)
 
表示日期时间的数据类型:
date
time
year
datetime
timestamp
 
在使用日期时间数据比较时常用如下
mysql> select * from tab ;
+------+---------------------+
| name | createtime          |
+------+---------------------+
| aaaa | 2013-05-14 17:20:19 |
| bbbb | 2013-04-14 17:20:36 |
| bbbb | 2013-04-13 17:20:36 |
| bbbb | 2013-04-15 17:20:36 |
+------+---------------------+
4 rows in set (0.00 sec)
mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2013-05-14 17:10:26 |
+---------------------+
1 row in set (0.00 sec)
 
mysql> select * from tab where createtime > now();
+------+---------------------+
| name | createtime          |
+------+---------------------+
| aaaa | 2013-05-14 17:20:19 |
+------+---------------------+
1 row in set (0.00 sec)
 
mysql> select current_timestamp;
+---------------------+
| current_timestamp   |
+---------------------+
| 2013-05-14 17:10:49 |
+---------------------+
1 row in set (0.00 sec)
 
mysql> select * from tab where createtime > current_timestamp;
+------+---------------------+
| name | createtime          |
+------+---------------------+
| aaaa | 2013-05-14 17:20:19 |
+------+---------------------+
1 row in set (0.00 sec)
 
mysql> select * from tab where createtime> str_to_date('2013-05-14 00:00:00','%Y-%m-%d %H:%i:%s');;
+------+---------------------+
| name | createtime          |
+------+---------------------+
| aaaa | 2013-05-14 17:20:19 |
+------+---------------------+
1 row in set (0.00 sec)
 
mysql> select * from tab where createtime between str_to_date('2013-05-14 00:00:00','%Y-%m-%d %H:%i:%s') and str_to_date('2013-05-15 00:00:00','%Y-%m-%d %H:%i:%s')
    -> ;
+------+---------------------+
| name | createtime          |
+------+---------------------+
| aaaa | 2013-05-14 17:20:19 |
+------+---------------------+
1 row in set (0.00 sec)
mysql> select * from tab where createtime between '2013-05-14 00:00:00' and '2013-05-15 00:00:00';
+------+---------------------+
| name | createtime          |
+------+---------------------+
| aaaa | 2013-05-14 17:20:19 |
+------+---------------------+
1 row in set (0.00 sec)
mysql>
 
2.数值函数
ABS(X) :返回表达式X的绝对值
mysql> select abs(-2);
+---------+
| abs(-2) |
+---------+
|       2 | 
+---------+
1 row in set (0.00 sec)
 
FLOOR(X) :返回不大于X的最大整数值
mysql> select floor(-2.45);
+--------------+
| floor(-2.45) |
+--------------+
|           -3 | 
+--------------+
1 row in set (0.00 sec)
 
MOD(N,M):模操作,返回N被M除后的余数。
mysql> select mod(3,2);
+----------+
| mod(3,2) |
+----------+
|        1 | 
+----------+
1 row in set (0.00 sec)
 
RAND()/RAND(N) :返回一个随机浮点值数a,范围在 0 到1 之间 (即, 其范围为 0 ≤ a ≤ 1.0)。若已指定一个整数参数 N,则它被用作种子值,用来产生重复序列。
mysql> select rand();
+-------------------+
| rand()            |
+-------------------+
| 0.294932589209576 | 
+-------------------+
1 row in set (0.00 sec)
mysql> select rand(2);
+-------------------+
| rand(2)           |
+-------------------+
| 0.655586646549019 | 
+-------------------+
1 row in set (0.00 sec)
 
ROUND(X)/ROUND(X,D) :返回参数X, 其值接近于最近似的整数。在有两个参数的情况下,返回 X ,其值保留到小数点后D位,而第D位的保留方式为四舍五入。若要接保留X值小数点左边的D位,可将D设为负值。
mysql> select round(2.4 );
+-------------+
| round(2.4 ) |
+-------------+
|           2 | 
+-------------+
1 row in set (0.00 sec)
mysql> select round(2.432,2 );
+-----------------+
| round(2.432,2 ) |
+-----------------+
|            2.43 | 
+-----------------+
1 row in set (0.00 sec)
mysql> select round(12.432,-1 );
+-------------------+
| round(12.432,-1 ) |
+-------------------+
|                10 | 
+-------------------+
1 row in set (0.00 sec)
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