獲得當(dāng)前日期+時(shí)間（date + time）函數(shù)：now()
mysql> select now();+---------------------+| now() |+---------------------+| 2008-08-08 22:20:46 |+---------------------+
獲得當(dāng)前日期+時(shí)間（date + time）函數(shù)：sysdate()
sysdate() 日期時(shí)間函數(shù)跟 now() 類(lèi)似，不同之處在于：now() 在執(zhí)行開(kāi)始時(shí)值就得到了， sysdate() 在函數(shù)執(zhí)行時(shí)動(dòng)態(tài)得到值?？聪旅娴睦泳兔靼琢耍?/p>
mysql> select now(), sleep(3), now();+---------------------+----------+---------------------+| now() | sleep(3) | now() |+---------------------+----------+---------------------+| 2008-08-08 22:28:21 | 0 | 2008-08-08 22:28:21 |+---------------------+----------+---------------------+
sysdate() 日期時(shí)間函數(shù)，一般情況下很少用到。
MySQL 獲得當(dāng)前時(shí)間戳函數(shù)：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 |+---------------------+---------------------+
MySQL 日期轉(zhuǎn)換函數(shù)、時(shí)間轉(zhuǎn)換函數(shù)
MySQL Date/Time to Str（日期/時(shí)間轉(zhuǎn)換為字符串）函數(shù)：date_format(date,format), time_format(time,format)
mysql> select date_format('2008-08-08 22:23:01', '%Y%m%d%H%i%s');+----------------------------------------------------+| date_format('2008-08-08 22:23:01', '%Y%m%d%H%i%s') |+----------------------------------------------------+| 20080808222301 |+----------------------------------------------------+MySQL 日期、時(shí)間轉(zhuǎn)換函數(shù)：date_format(date,format), time_format(time,format) 能夠把一個(gè)日期/時(shí)間轉(zhuǎn)換成各種各樣的字符串格式。它是 str_to_date(str,format) 函數(shù)的 一個(gè)逆轉(zhuǎn)換。
MySQL Str to Date （字符串轉(zhuǎn)換為日期）函數(shù)：str_to_date(str, format)
select str_to_date('08/09/2008', '%m/%d/%Y'); -- 2008-08-09select str_to_date('08/09/08' , '%m/%d/%y'); -- 2008-08-09select str_to_date('08.09.2008', '%m.%d.%Y'); -- 2008-08-09select str_to_date('08:09:30', '%h:%i:%s'); -- 08:09:30select str_to_date('08.09.2008 08:09:30', '%m.%d.%Y %h:%i:%s'); -- 2008-08-09 08:09:30可以看到，str_to_date(str,format) 轉(zhuǎn)換函數(shù)，可以把一些雜亂無(wú)章的字符串轉(zhuǎn)換為日期格式。另外，它也可以轉(zhuǎn)換為時(shí)間。“format” 可以參看 MySQL 手冊(cè)。
MySQL （日期、天數(shù)）轉(zhuǎn)換函數(shù)：to_days(date), from_days(days)
select to_days('0000-00-00'); -- 0select to_days('2008-08-08'); -- 733627 MySQL （時(shí)間、秒）轉(zhuǎn)換函數(shù)：time_to_sec(time), sec_to_time(seconds)
select time_to_sec('01:00:05'); -- 3605select sec_to_time(3605); -- '01:00:05'MySQL 拼湊日期、時(shí)間函數(shù)：makdedate(year,dayofyear), maketime(hour,minute,second)
select makedate(2001,31); -- '2001-01-31'select makedate(2001,32); -- '2001-02-01'select maketime(12,15,30); -- '12:15:30'
MySQL （Unix 時(shí)間戳、日期）轉(zhuǎn)換函數(shù)
unix_timestamp(),unix_timestamp(date),from_unixtime(unix_timestamp),from_unixtime(unix_timestamp,format)
下面是示例：
select unix_timestamp(); -- 1218290027select unix_timestamp('2008-08-08'); -- 1218124800select unix_timestamp('2008-08-08 12:30:00'); -- 1218169800select 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'MySQL 日期時(shí)間計(jì)算函數(shù)
MySQL 為日期增加一個(gè)時(shí)間間隔：date_add()
set @dt = now();select date_add(@dt, interval 1 day); -- add 1 dayselect date_add(@dt, interval 1 hour); -- add 1 hourselect date_add(@dt, interval 1 minute); -- ...select date_add(@dt, interval 1 second);select date_add(@dt, interval 1 microsecond);select date_add(@dt, interval 1 week);select date_add(@dt, interval 1 month);select date_add(@dt, interval 1 quarter);select date_add(@dt, interval 1 year);select date_add(@dt, interval -1 day); -- sub 1 day
MySQL adddate(), addtime()函數(shù)，可以用 date_add() 來(lái)替代。下面是 date_add() 實(shí)現(xiàn) addtime() 功能示例：
mysql> set @dt = '2008-08-09 12:12:33';mysql>mysql> select date_add(@dt, interval '01:15:30' hour_second);+------------------------------------------------+| date_add(@dt, interval '01:15:30' hour_second) |+------------------------------------------------+| 2008-08-09 13:28:03 |+------------------------------------------------+mysql> select date_add(@dt, interval '1 01:15:30' day_second);+-------------------------------------------------+| date_add(@dt, interval '1 01:15:30' day_second) |+-------------------------------------------------+| 2008-08-10 13:28:03 |+-------------------------------------------------+
MySQL 為日期減去一個(gè)時(shí)間間隔：date_sub()
mysql> select date_sub('1998-01-01 00:00:00', interval '1 1:1:1' day_second);+----------------------------------------------------------------+| date_sub('1998-01-01 00:00:00', interval '1 1:1:1' day_second) |+----------------------------------------------------------------+| 1997-12-30 22:58:59 |+----------------------------------------------------------------+MySQL date_sub() 日期時(shí)間函數(shù) 和 date_add() 用法一致，不再贅述。
MySQL 日期、時(shí)間相減函數(shù)：datediff(date1,date2), timediff(time1,time2)
MySQL datediff(date1,date2)：兩個(gè)日期相減 date1 - date2，返回天數(shù)。
select datediff('2008-08-08', '2008-08-01'); -- 7select datediff('2008-08-01', '2008-08-08'); -- -7MySQL timediff(time1,time2)：兩個(gè)日期相減 time1 - time2，返回 time 差值。select timediff('2008-08-08 08:08:08', '2008-08-08 00:00:00'); -- 08:08:08select timediff('08:08:08', '00:00:00'); -- 08:08:08注意：timediff(time1,time2) 函數(shù)的兩個(gè)參數(shù)類(lèi)型必須相同。
MySQL 時(shí)間戳（timestamp）轉(zhuǎn)換、增、減函數(shù)：
timestamp(date) -- date to timestamptimestamp(dt,time) -- dt + timetimestampadd(unit,interval,datetime_expr) --timestampdiff(unit,datetime_expr1,datetime_expr2) --
請(qǐng)看示例部分：
select timestamp('2008-08-08'); -- 2008-08-08 00:00:00select timestamp('2008-08-08 08:00:00', '01:01:01'); -- 2008-08-08 09:01:01select timestamp('2008-08-08 08:00:00', '10 01:01:01'); -- 2008-08-18 09:01:01select timestampadd(day, 1, '2008-08-08 08:00:00'); -- 2008-08-09 08:00:00select date_add('2008-08-08 08:00:00', interval 1 day); -- 2008-08-09 08:00:00MySQL timestampadd() 函數(shù)類(lèi)似于 date_add()。select timestampdiff(year,'2002-05-01','2001-01-01'); -- -1select timestampdiff(day ,'2002-05-01','2001-01-01'); -- -485select timestampdiff(hour,'2008-08-08 12:00:00','2008-08-08 00:00:00'); -- -12select datediff('2008-08-08 12:00:00', '2008-08-01 00:00:00'); -- 7MySQL timestampdiff() 函數(shù)就比 datediff() 功能強(qiáng)多了，datediff() 只能計(jì)算兩個(gè)日期（date）之間相差的天數(shù)。
MySQL 時(shí)區(qū)（timezone）轉(zhuǎn)換函數(shù)
convert_tz(dt,from_tz,to_tz)
select convert_tz('2008-08-08 12:00:00', '+08:00', '+00:00'); -- 2008-08-08 04:00:00時(shí)區(qū)轉(zhuǎn)換也可以通過(guò) date_add, date_sub, timestampadd 來(lái)實(shí)現(xiàn)。
select date_add('2008-08-08 12:00:00', interval -8 hour); -- 2008-08-08 04:00:00select date_sub('2008-08-08 12:00:00', interval 8 hour); -- 2008-08-08 04:00:00select timestampadd(hour, -8, '2008-08-08 12:00:00'); -- 2008-08-08 04:00:00以上所述是小編給大家介紹的MySQL 獲得當(dāng)前日期時(shí)間 函數(shù)，希望對(duì)大家有所幫助，如果大家有任何疑問(wèn)歡迎給我留言，小編會(huì)及時(shí)回復(fù)大家的！
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