mysql常用日期时间/数值函数_MySQL

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_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)