7.1 KiB
unix_timestamp
description
Syntax: UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date)
将Date或者Datetime类型转化为unix时间戳 如果没有参数，则是将当前的时间转化为时间戳 参数需要是Date或者Datetime类型
example
mysql> SELECT UNIX_TIMESTAMP(); -> 1196440210 mysql> SELECT UNIX_TIMESTAMP('2007-11-30 10:30:19'); -> 1196418619
from_unixtime
description
Syntax: FROM_UNIXTIME(int unix_timestamp[, string string_format])
将unix时间戳转化位对应的time格式，返回的格式由string_format指定 默认为yyyy-MM-dd HH:mm:ss 传入的是整形，返回的是字符串类型 目前string_format只支持两种类型的格式：yyyy-MM-dd，yyyy-MM-dd HH:mm:ss 其余string_format格式是非法的，返回NULL
example
mysql> SELECT FROM_UNIXTIME(1196440219); -> '2007-12-01 00:30:19'
mysql> SELECT FROM_UNIXTIME(1196440219, 'yyyy-MM-dd'); -> '2007-12-01'
mysql> SELECT FROM_UNIXTIME(1196440219, 'yyyy-MM-dd HH:mm:ss'); -> '2007-12-01 00:30:19'
year
description
Syntax: YEAR(date)
返回date类型的year部分，范围从1000-9999 参数为Date或者Datetime类型
example
mysql> SELECT YEAR('1987-01-01'); -> 1987
month
description
Syntax: MONTH(date)
返回时间类型中的月份信息，范围是1, 12 参数为Date或者Datetime类型
example
mysql> SELECT MONTH('1987-01-02'); -> 01
day
description
Syntax: DAY(date)
与DAYOFMONTH是同义词，请help dayofmonth
dayofmonth
description
Syntax: DAYOFMONTH(date)
获得日期中的天信息，返回值范围从1-31。 需要传入date类型
example
mysql> SELECT DAYOFMONTH('1987-01-02'); -> 2
dayofyear
description
Syntax: DAYOFYEAR(date)
获得日期中对应当年中的哪一天。 输入值为date类型
example
mysql> SELECT DAYOFYEAR('2007-02-03'); -> 34
weekofyear
description
Syntax: WEEKOFYEAR(date)
获得一年中的第几周 输入值为date类型
example
mysql> SELECT WEEKOFYEAR('2008-02-20'); -> 8
hour
description
Syntax: HOUR(date)
获得时间中对应的小时信息 这里Palo跟MySQL不太一样，因为MySQL是支持Time类型的 Palo没有Time类型，所以输入的内容是Date或者Datetime。
example
mysql> select hour("2000-01-02 12:34:56"); -> 12
minute
description
Syntax: MINUTE(date)
获得日期中的分钟信息 这里Palo跟MySQL不太一样，因为MySQL是支持Time类型的 Palo没有Time类型，所以输入的内容是Date或者Datetime。
example
mysql> SELECT MINUTE("2000-01-02 12:34:56"); -> 34
second
description
Syntax: SECOND(date)
获得时间中的秒信息 这里Palo跟MySQL不太一样，因为MySQL是支持Time类型的 Palo没有Time类型，所以输入的内容是Date或者Datetime。
example
mysql> SELECT SECOND("2000-01-02 12:34:56"); -> 56
now
description
Syntax: NOW()
获得当前的时间，以Datetime类型返回
example
mysql> SELECT NOW(); -> '2007-12-15 23:50:26'
current_timestamp
description
Syntax: CURRENT_TIMESTAMP()
与NOW()是同义词
datediff
description
Syntax: DATEDIFF(expr1,expr2)
计算expr1 - expr2，结果精确到天。 要求传入的两个值需要是datetime类型。
example
mysql> SELECT DATEDIFF(CAST ('2007-12-31 23:59:59' AS DATETIME),CAST ('2007-12-30' AS DATETIME)); -> 1 mysql> SELECT DATEDIFF(CAST('2010-11-30 23:59:59' AS DATETIME), CAST('2010-12-31' AS DATETIME)); -> -31
date_add
description
Syntax: DATE_ADD(date,INTERVAL expr unit)
对时间类型进行加法运算 支持的time unit包括 YEAR, MONTH, DAY, HOUR, MINUTE, SECOND
example
mysql> DATE_ADD(date,INTERVAL expr unit) -> 1987-01-02 00:00:00
date_sub
description
Syntax: DATE_SUB(date,INTERVAL expr unit)
与DATE_ADD相反，对时间类型进行减法运算 支持的time unit包括 YEAR, MONTH, DAY, HOUR, MINUTE, SECOND
example
mysql> DATE_SUB(date,INTERVAL expr unit) -> 1986-12-31 00:00:00
date_format
description
Syntax: DATE_FORMAT(date, format)
将日期类型按照format的类型转化位字符串， 当前支持最大128字节的字符串，如果返回值长度超过128，则返回NULL format的含义如下： %a Abbreviated weekday name (Sun..Sat) %b Abbreviated month name (Jan..Dec) %c Month, numeric (0..12) %D Day of the month with English suffix (0th, 1st, 2nd, 3rd, …) %d Day of the month, numeric (00..31) %e Day of the month, numeric (0..31) %f Microseconds (000000..999999) %H Hour (00..23) %h Hour (01..12) %I Hour (01..12) %i Minutes, numeric (00..59) %j Day of year (001..366) %k Hour (0..23) %l Hour (1..12) %M Month name (January..December) %m Month, numeric (00..12) %p AM or PM %r Time, 12-hour (hh:mm:ss followed by AM or PM) %S Seconds (00..59) %s Seconds (00..59) %T Time, 24-hour (hh:mm:ss) %U Week (00..53), where Sunday is the first day of the week; WEEK() mode 0 %u Week (00..53), where Monday is the first day of the week; WEEK() mode 1 %V Week (01..53), where Sunday is the first day of the week; WEEK() mode 2; used with %X %v Week (01..53), where Monday is the first day of the week; WEEK() mode 3; used with %x %W Weekday name (Sunday..Saturday) %w Day of the week (0=Sunday..6=Saturday) %X Year for the week where Sunday is the first day of the week, numeric, four digits; used with %V %x Year for the week, where Monday is the first day of the week, numeric, four digits; used with %v %Y Year, numeric, four digits %y Year, numeric (two digits) %% A literal “%” character %x x, for any “x” not listed above
example
mysql> SELECT DATE_FORMAT('2009-10-04 22:23:00', '%W %M %Y'); -> 'Sunday October 2009' mysql> SELECT DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s'); -> '22:23:00' mysql> SELECT DATE_FORMAT('1900-10-04 22:23:00', '%D %y %a %d %m %b %j'); -> '4th 00 Thu 04 10 Oct 277' mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00', '%H %k %I %r %T %S %w'); -> '22 22 10 10:23:00 PM 22:23:00 00 6' mysql> SELECT DATE_FORMAT('1999-01-01', '%X %V'); -> '1998 52' mysql> SELECT DATE_FORMAT('2006-06-01', '%d'); -> '01'
from_days
description
Syntax: FROM_DAYS(N) 通过距离0000-01-01日的天数计算出哪一天
example
mysql> SELECT FROM_DAYS(730669); -> '2007-07-03'
to_days
description
Syntax: TO_DAYS(date) 返回date距离0000-01-01的天数
example
mysql> SELECT TO_DAYS(950501); -> 728779 mysql> SELECT TO_DAYS('2007-10-07'); -> 733321
str_to_date
description
Syntax: STR_TO_DATE(str, format) 通过format指定的方式将str转化为DATE类型，如果转化结果不对返回NULL 支持的format格式与date_format一致
example
mysql> SELECT STR_TO_DATE('2014-12-21 12:34:56', '%Y-%m-%d %H:%i:%s'); -> 2014-12-21 12:34:56 mysql> SELECT STR_TO_DATE('200442 Monday', '%X%V %W'); -> 2004-10-18
monthname
description
Syntax: MONTHNAME(DATE)
返回日期对应的月份名字
example
mysql> SELECT MONTHNAME('2008-02-03'); -> 'February'
monthname
description
Syntax: MONTHNAME(DATE)
返回日期对应的日期名字
example
mysql> SELECT DAYNAME('2007-02-03'); -> 'Saturday'