《Mysql實(shí)例MySQL日期數(shù)據(jù)類型、時(shí)間類型使用總結(jié)》要點(diǎn)：
本文介紹了Mysql實(shí)例MySQL日期數(shù)據(jù)類型、時(shí)間類型使用總結(jié)，希望對(duì)您有用。如果有疑問(wèn)，可以聯(lián)系我們。
MYSQL數(shù)據(jù)庫(kù)MySQL 日期類型：日期格式、所占存儲(chǔ)空間、日期范圍 比較.
日期類型??????? 存儲(chǔ)空間?????? 日期格式???????????????? 日期范圍
------------ ---------?? --------------------- -----------------------------------------
datetime?????? 8 bytes?? YYYY-MM-DD HH:MM:SS?? 1000-01-01 00:00:00 ~ 9999-12-31 23:59:59
timestamp????? 4 bytes?? YYYY-MM-DD HH:MM:SS?? 1970-01-01 00:00:01 ~ 2038
date?????????? 3 bytes?? YYYY-MM-DD??????????? 1000-01-01????????? ~ 9999-12-31
year?????????? 1 bytes?? YYYY????????????????? 1901??????????????? ~ 2155
MYSQL數(shù)據(jù)庫(kù)在 MySQL 中創(chuàng)建表時(shí),對(duì)照上面的表格,很容易就能選擇到合適自己的數(shù)據(jù)類型.不過(guò)到底是選擇 datetime 還是 timestamp,可能會(huì)有點(diǎn)犯難.這兩個(gè)日期時(shí)間類型各有優(yōu)點(diǎn)：datetime 的日期范圍比較大；timestamp 所占存儲(chǔ)空間比較小,只是 datetime 的一半.
MYSQL數(shù)據(jù)庫(kù)另外,timestamp 類型的列還有個(gè)特性：默認(rèn)情況下,在 insert, update 數(shù)據(jù)時(shí),timestamp 列會(huì)自動(dòng)以當(dāng)前時(shí)間(CURRENT_TIMESTAMP)填充/更新.“自動(dòng)”的意思就是,你不去管它,MySQL 會(huì)替你去處理.
?
MYSQL數(shù)據(jù)庫(kù)建表的代碼為:
MYSQL數(shù)據(jù)庫(kù)create table t8 (
? `id1` timestamp NOT NULL default CURRENT_TIMESTAMP,
? `id2` datetime default NULL
);
MYSQL數(shù)據(jù)庫(kù)
一般情況下,我傾向于使用 datetime 日期類型.
MYSQL數(shù)據(jù)庫(kù)兩者之間的比較:
MYSQL數(shù)據(jù)庫(kù)1. timestamp容易所支持的范圍比timedate要小. 并且容易出現(xiàn)超出的情況
MYSQL數(shù)據(jù)庫(kù)2.timestamp比較受時(shí)區(qū)timezone的影響以及MYSQL版本和服務(wù)器的SQL MODE的影響.
MYSQL數(shù)據(jù)庫(kù)
MySQL 時(shí)間類型：時(shí)間格式、所占存儲(chǔ)空間、時(shí)間范圍.
時(shí)間類型??????? 存儲(chǔ)空間????? 時(shí)間格式???????????????? 時(shí)間范圍
------------ ---------?? --------------------- -----------------------------------------
time?????????? 3 bytes?? HH:MM:SS????????????? -838:59:59????????? ~ 838:59:59
MYSQL數(shù)據(jù)庫(kù)time 時(shí)間范圍居然有這么大的范圍,特別是 time 可以取負(fù)值,有點(diǎn)奇怪.后來(lái),看了 MySQL 手冊(cè)才知道這是為了滿足兩個(gè)日期時(shí)間相減才這樣設(shè)計(jì)的.
MYSQL數(shù)據(jù)庫(kù)select timediff('2000:01:31 23:59:59', '2000:01:01 00:00:00'); -- 743:59:59
select timediff('2000:01:01 00:00:00', '2000:01:31 23:59:59'); -- -743:59:59
select timediff('23:59:59', '12:00:00');??????????????????????? -- 11:59:59
MYSQL數(shù)據(jù)庫(kù)注意,timediff 的兩個(gè)參數(shù)只能是 datetime/timestamp, time 類型的,并且這兩個(gè)參數(shù)類型要相同.即：datetime/timestamp 和 datetime/timestamp 比較；time 和 time 相比較.
MYSQL數(shù)據(jù)庫(kù)雖然 MySQL 中的日期時(shí)間類型比較豐富,但遺憾的是,目前(2008-08-08)這些日期時(shí)間類型只能支持到秒級(jí)別,不支持毫秒、微秒.也沒(méi)有產(chǎn)生毫秒的函數(shù).
MYSQL數(shù)據(jù)庫(kù)
《MySQL：MySQL日期數(shù)據(jù)類型、MySQL時(shí)間類型使用總結(jié)》適用于 MySQL 5.X 及以上版本.
MYSQL數(shù)據(jù)庫(kù)一、MySQL 獲得當(dāng)前日期時(shí)間 函數(shù)
1.1 獲得當(dāng)前日期+時(shí)間(date + time)函數(shù)：now()
MYSQL數(shù)據(jù)庫(kù)mysql> select now();
MYSQL數(shù)據(jù)庫(kù)+---------------------+
| now()?????????????? |
+---------------------+
| 2008-08-08 22:20:46 |
+---------------------+
MYSQL數(shù)據(jù)庫(kù)除了 now() 函數(shù)能獲得當(dāng)前的日期時(shí)間外,MySQL 中還有下面的函數(shù)：
MYSQL數(shù)據(jù)庫(kù)current_timestamp()
,current_timestamp
,localtime()
,localtime
,localtimestamp??? -- (v4.0.6)
,localtimestamp() -- (v4.0.6)
MYSQL數(shù)據(jù)庫(kù)這些日期時(shí)間函數(shù),都等同于 now().鑒于 now() 函數(shù)簡(jiǎn)短易記,建議總是使用 now() 來(lái)替代上面列出的函數(shù).
MYSQL數(shù)據(jù)庫(kù)1.2 獲得當(dāng)前日期+時(shí)間(date + time)函數(shù)：sysdate()
MYSQL數(shù)據(jù)庫(kù)sysdate() 日期時(shí)間函數(shù)跟 now() 類似,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.看下面的例子就明白了：
MYSQL數(shù)據(jù)庫(kù)mysql> select now(), sleep(3), now();
MYSQL數(shù)據(jù)庫(kù)+---------------------+----------+---------------------+
| now()?????????????? | sleep(3) | now()?????????????? |
+---------------------+----------+---------------------+
| 2008-08-08 22:28:21 |??????? 0 | 2008-08-08 22:28:21 |
+---------------------+----------+---------------------+
MYSQL數(shù)據(jù)庫(kù)mysql> select sysdate(), sleep(3), sysdate();
MYSQL數(shù)據(jù)庫(kù)+---------------------+----------+---------------------+
| sysdate()?????????? | sleep(3) | sysdate()?????????? |
+---------------------+----------+---------------------+
| 2008-08-08 22:28:41 |??????? 0 | 2008-08-08 22:28:44 |
+---------------------+----------+---------------------+
MYSQL數(shù)據(jù)庫(kù)可以看到,雖然中途 sleep 3 秒,但 now() 函數(shù)兩次的時(shí)間值是相同的； sysdate() 函數(shù)兩次得到的時(shí)間值相差 3 秒.MySQL Manual 中是這樣描述 sysdate() 的：Return the time at which the function executes.
MYSQL數(shù)據(jù)庫(kù)sysdate() 日期時(shí)間函數(shù),一般情況下很少用到.
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MYSQL數(shù)據(jù)庫(kù)
2. 獲得當(dāng)前日期(date)函數(shù)：curdate()
MYSQL數(shù)據(jù)庫(kù)mysql> select curdate();
MYSQL數(shù)據(jù)庫(kù)+------------+
| curdate() |
+------------+
| 2008-08-08 |
+------------+
MYSQL數(shù)據(jù)庫(kù)其中,下面的兩個(gè)日期函數(shù)等同于 curdate()：
MYSQL數(shù)據(jù)庫(kù)current_date()
,current_date
MYSQL數(shù)據(jù)庫(kù)3. 獲得當(dāng)前時(shí)間(time)函數(shù)：curtime()
MYSQL數(shù)據(jù)庫(kù)mysql> select curtime();
MYSQL數(shù)據(jù)庫(kù)+-----------+
| curtime() |
+-----------+
| 22:41:30 |
+-----------+
MYSQL數(shù)據(jù)庫(kù)其中,下面的兩個(gè)時(shí)間函數(shù)等同于 curtime()：
MYSQL數(shù)據(jù)庫(kù)current_time()
,current_time
MYSQL數(shù)據(jù)庫(kù)4. 獲得當(dāng)前 UTC 日期時(shí)間函數(shù)：utc_date(), utc_time(), utc_timestamp()
MYSQL數(shù)據(jù)庫(kù)mysql> select utc_timestamp(), utc_date(), utc_time(), now()
MYSQL數(shù)據(jù)庫(kù)+---------------------+------------+------------+---------------------+
| utc_timestamp()???? | utc_date() | utc_time() | now()?????????????? |
+---------------------+------------+------------+---------------------+
| 2008-08-08 14:47:11 | 2008-08-08 | 14:47:11?? | 2008-08-08 22:47:11 |
+---------------------+------------+------------+---------------------+
MYSQL數(shù)據(jù)庫(kù)因?yàn)槲覈?guó)位于東八時(shí)區(qū),所以本地時(shí)間 = UTC 時(shí)間 + 8 小時(shí).UTC 時(shí)間在業(yè)務(wù)涉及多個(gè)國(guó)家和地區(qū)的時(shí)候,非常有用.
MYSQL數(shù)據(jù)庫(kù)?
MYSQL數(shù)據(jù)庫(kù)?
MYSQL數(shù)據(jù)庫(kù)
五、MySQL 時(shí)間戳(Timestamp)函數(shù)
1. MySQL 獲得當(dāng)前時(shí)間戳函數(shù)：current_timestamp, current_timestamp()
MYSQL數(shù)據(jù)庫(kù)mysql> select current_timestamp, current_timestamp();
MYSQL數(shù)據(jù)庫(kù)+---------------------+---------------------+
| current_timestamp?? | current_timestamp() |
+---------------------+---------------------+
| 2008-08-09 23:22:24 | 2008-08-09 23:22:24 |
+---------------------+---------------------+
MYSQL數(shù)據(jù)庫(kù)2. MySQL (Unix 時(shí)間戳、日期)轉(zhuǎn)換函數(shù)：
MYSQL數(shù)據(jù)庫(kù)unix_timestamp(),
unix_timestamp(date),
from_unixtime(unix_timestamp),
from_unixtime(unix_timestamp,format)
MYSQL數(shù)據(jù)庫(kù)下面是示例：
MYSQL數(shù)據(jù)庫(kù)select unix_timestamp();?????????????????????? -- 1218290027??????????? ===得到當(dāng)前時(shí)間的UNIX時(shí)間值
MYSQL數(shù)據(jù)庫(kù)?
MYSQL數(shù)據(jù)庫(kù)將具體時(shí)間來(lái)轉(zhuǎn)換成timestamp
MYSQL數(shù)據(jù)庫(kù)select unix_timestamp('2008-08-08');?????????? -- 1218124800
select unix_timestamp('2008-08-08 12:30:00'); -- 1218169800
MYSQL數(shù)據(jù)庫(kù)
將timestamp來(lái)轉(zhuǎn)換成具體時(shí)間
select 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'
MYSQL數(shù)據(jù)庫(kù)select from_unixtime(1218169800, '%Y %D %M %h:%i:%s %x'); -- '2008 8th August 12:30:00 2008'
MYSQL數(shù)據(jù)庫(kù)?
MYSQL數(shù)據(jù)庫(kù)?
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MYSQL數(shù)據(jù)庫(kù)3. MySQL 時(shí)間戳(timestamp)轉(zhuǎn)換、增、減函數(shù)：
MYSQL數(shù)據(jù)庫(kù)timestamp(date)???????????????????????????????????? -- date to timestamp
timestamp(dt,time)????????????????????????????????? -- dt + time
timestampadd(unit,interval,datetime_expr)?????????? --
timestampdiff(unit,datetime_expr1,datetime_expr2)?? --
MYSQL數(shù)據(jù)庫(kù)請(qǐng)看示例部分：
MYSQL數(shù)據(jù)庫(kù)select timestamp('2008-08-08');???????????????????????? -- 2008-08-08 00:00:00
select timestamp('2008-08-08 08:00:00', '01:01:01');??? -- 2008-08-08 09:01:01
select timestamp('2008-08-08 08:00:00', '10 01:01:01'); -- 2008-08-18 09:01:01
MYSQL數(shù)據(jù)庫(kù)select timestampadd(day, 1, '2008-08-08 08:00:00');???? -- 2008-08-09 08:00:00
select date_add('2008-08-08 08:00:00', interval 1 day); -- 2008-08-09 08:00:00
MYSQL數(shù)據(jù)庫(kù)MySQL timestampadd() 函數(shù)類似于 date_add().
MYSQL數(shù)據(jù)庫(kù)select timestampdiff(year,'2002-05-01','2001-01-01');??????????????????? -- -1
select timestampdiff(day ,'2002-05-01','2001-01-01');??????????????????? -- -485
select timestampdiff(hour,'2008-08-08 12:00:00','2008-08-08 00:00:00'); -- -12
MYSQL數(shù)據(jù)庫(kù)select datediff('2008-08-08 12:00:00', '2008-08-01 00:00:00');?????????? -- 7
MYSQL數(shù)據(jù)庫(kù)MySQL 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數(shù)據(jù)庫(kù)?
MYSQL數(shù)據(jù)庫(kù)?
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MYSQL數(shù)據(jù)庫(kù)====================================================================================
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MYSQL數(shù)據(jù)庫(kù)
二、MySQL 日期時(shí)間 Extract(選取) 函數(shù).
1. 選取日期時(shí)間的各個(gè)部分：日期、時(shí)間、年、季度、月、日、小時(shí)、分鐘、秒、微秒
MYSQL數(shù)據(jù)庫(kù)set @dt = '2008-09-10 07:15:30.123456';
MYSQL數(shù)據(jù)庫(kù)select date(@dt);??????? -- 2008-09-10
select time(@dt);??????? -- 07:15:30.123456
select year(@dt);??????? -- 2008
select quarter(@dt);???? -- 3
select month(@dt);?????? -- 9
select week(@dt);??????? -- 36
select day(@dt);???????? -- 10
select hour(@dt);??????? -- 7
select minute(@dt);????? -- 15
select second(@dt);????? -- 30
select microsecond(@dt); -- 123456
MYSQL數(shù)據(jù)庫(kù)2. MySQL Extract() 函數(shù),可以上面實(shí)現(xiàn)類似的功能：
MYSQL數(shù)據(jù)庫(kù)set @dt = '2008-09-10 07:15:30.123456';
MYSQL數(shù)據(jù)庫(kù)select extract(year??????????????? from @dt); -- 2008
select extract(quarter???????????? from @dt); -- 3
select extract(month?????????????? from @dt); -- 9
select extract(week??????????????? from @dt); -- 36
select extract(day???????????????? from @dt); -- 10
select extract(hour??????????????? from @dt); -- 7
select extract(minute????????????? from @dt); -- 15
select extract(second????????????? from @dt); -- 30
select extract(microsecond???????? from @dt); -- 123456
MYSQL數(shù)據(jù)庫(kù)select extract(year_month????????? from @dt); -- 200809
select extract(day_hour??????????? from @dt); -- 1007
select extract(day_minute????????? from @dt); -- 100715
select extract(day_second????????? from @dt); -- 10071530
select extract(day_microsecond???? from @dt); -- 10071530123456
select extract(hour_minute???????? from @dt); --??? 715
select extract(hour_second???????? from @dt); --??? 71530
select extract(hour_microsecond??? from @dt); --??? 71530123456
select extract(minute_second?????? from @dt); --????? 1530
select extract(minute_microsecond from @dt); --????? 1530123456
select extract(second_microsecond from @dt); --??????? 30123456
MYSQL數(shù)據(jù)庫(kù)MySQL Extract() 函數(shù)除了沒(méi)有date(),time() 的功能外,其他功能一應(yīng)具全.并且還具有選取‘day_microsecond' 等功能.注意這里不是只選取 day 和 microsecond,而是從日期的 day 部分一直選取到 microsecond 部分.夠強(qiáng)悍的吧!
MYSQL數(shù)據(jù)庫(kù)MySQL Extract() 函數(shù)唯一不好的地方在于：你需要多敲幾次鍵盤.
MYSQL數(shù)據(jù)庫(kù)3. MySQL dayof... 函數(shù)：dayofweek(), dayofmonth(), dayofyear()
MYSQL數(shù)據(jù)庫(kù)分別返回日期參數(shù),在一周、一月、一年中的位置.
MYSQL數(shù)據(jù)庫(kù)set @dt = '2008-08-08';
MYSQL數(shù)據(jù)庫(kù)select dayofweek(@dt);?? -- 6
select dayofmonth(@dt); -- 8
select dayofyear(@dt);?? -- 221
MYSQL數(shù)據(jù)庫(kù)日期 '2008-08-08' 是一周中的第 6 天(1 = Sunday, 2 = Monday, ..., 7 = Saturday)；一月中的第 8 天；一年中的第 221 天.
MYSQL數(shù)據(jù)庫(kù)4. MySQL week... 函數(shù)：week(), weekofyear(), dayofweek(), weekday(), yearweek()
MYSQL數(shù)據(jù)庫(kù)set @dt = '2008-08-08';
MYSQL數(shù)據(jù)庫(kù)select week(@dt);??????? -- 31
select week(@dt,3);????? -- 32
select weekofyear(@dt); -- 32
MYSQL數(shù)據(jù)庫(kù)select dayofweek(@dt);?? -- 6
select weekday(@dt);???? -- 4
MYSQL數(shù)據(jù)庫(kù)select yearweek(@dt);??? -- 200831
MYSQL數(shù)據(jù)庫(kù)MySQL week() 函數(shù),可以有兩個(gè)參數(shù),具體可看手冊(cè). weekofyear() 和 week() 一樣,都是計(jì)算“某天”是位于一年中的第幾周. weekofyear(@dt) 等價(jià)于 week(@dt,3).
MYSQL數(shù)據(jù)庫(kù)MySQL weekday() 函數(shù)和 dayofweek() 類似,都是返回“某天”在一周中的位置.不同點(diǎn)在于參考的標(biāo)準(zhǔn), weekday：(0 = Monday, 1 = Tuesday, ..., 6 = Sunday)； dayofweek：(1 = Sunday, 2 = Monday, ..., 7 = Saturday)
MYSQL數(shù)據(jù)庫(kù)MySQL yearweek() 函數(shù),返回 year(2008) + week 位置(31).
MYSQL數(shù)據(jù)庫(kù)5. MySQL 返回星期和月份名稱函數(shù)：dayname(), monthname()
MYSQL數(shù)據(jù)庫(kù)set @dt = '2008-08-08';
MYSQL數(shù)據(jù)庫(kù)select dayname(@dt);???? -- Friday
select monthname(@dt);?? -- August
MYSQL數(shù)據(jù)庫(kù)思考,如何返回中文的名稱呢?
MYSQL數(shù)據(jù)庫(kù)6. MySQL last_day() 函數(shù)：返回月份中的最后一天.
MYSQL數(shù)據(jù)庫(kù)select last_day('2008-02-01'); -- 2008-02-29
select last_day('2008-08-08'); -- 2008-08-31
MYSQL數(shù)據(jù)庫(kù)MySQL last_day() 函數(shù)非常有用,比如我想得到當(dāng)前月份中有多少天,可以這樣來(lái)計(jì)算：
MYSQL數(shù)據(jù)庫(kù)mysql> select now(), day(last_day(now())) as days;
MYSQL數(shù)據(jù)庫(kù)+---------------------+------+
| now()?????????????? | days |
+---------------------+------+
| 2008-08-09 11:45:45 |?? 31 |
+---------------------+------+
MYSQL數(shù)據(jù)庫(kù)三、MySQL 日期時(shí)間計(jì)算函數(shù)
1. MySQL 為日期增加一個(gè)時(shí)間間隔：date_add()
MYSQL數(shù)據(jù)庫(kù)set @dt = now();
MYSQL數(shù)據(jù)庫(kù)select date_add(@dt, interval 1 day);??????? -- add 1 day
select date_add(@dt, interval 1 hour);?????? -- add 1 hour
select 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);
MYSQL數(shù)據(jù)庫(kù)select date_add(@dt, interval -1 day);?????? -- sub 1 day
MYSQL數(shù)據(jù)庫(kù)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數(shù)據(jù)庫(kù)mysql> set @dt = '2008-08-09 12:12:33';
MYSQL數(shù)據(jù)庫(kù)mysql>
mysql> select date_add(@dt, interval '01:15:30' hour_second);
MYSQL數(shù)據(jù)庫(kù)+------------------------------------------------+
| date_add(@dt, interval '01:15:30' hour_second) |
+------------------------------------------------+
| 2008-08-09 13:28:03??????????????????????????? |
+------------------------------------------------+
MYSQL數(shù)據(jù)庫(kù)mysql> select date_add(@dt, interval '1 01:15:30' day_second);
MYSQL數(shù)據(jù)庫(kù)+-------------------------------------------------+
| date_add(@dt, interval '1 01:15:30' day_second) |
+-------------------------------------------------+
| 2008-08-10 13:28:03???????????????????????????? |
+-------------------------------------------------+
MYSQL數(shù)據(jù)庫(kù)date_add() 函數(shù),分別為 @dt 增加了“1小時(shí) 15分 30秒” 和 “1天 1小時(shí) 15分 30秒”.建議：總是使用 date_add() 日期時(shí)間函數(shù)來(lái)替代 adddate(), addtime().
MYSQL數(shù)據(jù)庫(kù)2. MySQL 為日期減去一個(gè)時(shí)間間隔：date_sub()
MYSQL數(shù)據(jù)庫(kù)mysql> select date_sub('1998-01-01 00:00:00', interval '1 1:1:1' day_second);
MYSQL數(shù)據(jù)庫(kù)+----------------------------------------------------------------+
| date_sub('1998-01-01 00:00:00', interval '1 1:1:1' day_second) |
+----------------------------------------------------------------+
| 1997-12-30 22:58:59??????????????????????????????????????????? |
+----------------------------------------------------------------+
MYSQL數(shù)據(jù)庫(kù)MySQL date_sub() 日期時(shí)間函數(shù) 和 date_add() 用法一致,不再贅述.另外,MySQL 中還有兩個(gè)函數(shù) subdate(), subtime(),建議,用 date_sub() 來(lái)替代.
MYSQL數(shù)據(jù)庫(kù)3. MySQL 另類日期函數(shù)：period_add(P,N), period_diff(P1,P2)
MYSQL數(shù)據(jù)庫(kù)函數(shù)參數(shù)“P” 的格式為“YYYYMM” 或者 “YYMM”,第二個(gè)參數(shù)“N” 表示增加或減去 N month(月).
MYSQL數(shù)據(jù)庫(kù)MySQL period_add(P,N)：日期加/減去N月.
MYSQL數(shù)據(jù)庫(kù)mysql> select period_add(200808,2), period_add(20080808,-2)
MYSQL數(shù)據(jù)庫(kù)+----------------------+-------------------------+
| period_add(200808,2) | period_add(20080808,-2) |
+----------------------+-------------------------+
|?????????????? 200810 |??????????????? 20080806 |
+----------------------+-------------------------+
MYSQL數(shù)據(jù)庫(kù)MySQL period_diff(P1,P2)：日期 P1-P2,返回 N 個(gè)月.
MYSQL數(shù)據(jù)庫(kù)mysql> select period_diff(200808, 200801);
MYSQL數(shù)據(jù)庫(kù)+-----------------------------+
| period_diff(200808, 200801) |
+-----------------------------+
|?????????????????????????? 7 |
+-----------------------------+
MYSQL數(shù)據(jù)庫(kù)在 MySQL 中,這兩個(gè)日期函數(shù),一般情況下很少用到.
MYSQL數(shù)據(jù)庫(kù)4. MySQL 日期、時(shí)間相減函數(shù)：datediff(date1,date2), timediff(time1,time2)
MYSQL數(shù)據(jù)庫(kù)MySQL datediff(date1,date2)：兩個(gè)日期相減 date1 - date2,返回天數(shù).
MYSQL數(shù)據(jù)庫(kù)select datediff('2008-08-08', '2008-08-01'); -- 7
select datediff('2008-08-01', '2008-08-08'); -- -7
MYSQL數(shù)據(jù)庫(kù)MySQL timediff(time1,time2)：兩個(gè)日期相減 time1 - time2,返回 time 差值.
MYSQL數(shù)據(jù)庫(kù)select timediff('2008-08-08 08:08:08', '2008-08-08 00:00:00'); -- 08:08:08
select timediff('08:08:08', '00:00:00');?????????????????????? -- 08:08:08
MYSQL數(shù)據(jù)庫(kù)注意：timediff(time1,time2) 函數(shù)的兩個(gè)參數(shù)類型必須相同.
MYSQL數(shù)據(jù)庫(kù)四、MySQL 日期轉(zhuǎn)換函數(shù)、時(shí)間轉(zhuǎn)換函數(shù)
1. MySQL (時(shí)間、秒)轉(zhuǎn)換函數(shù)：time_to_sec(time), sec_to_time(seconds)
MYSQL數(shù)據(jù)庫(kù)select time_to_sec('01:00:05'); -- 3605
select sec_to_time(3605);??????? -- '01:00:05'
MYSQL數(shù)據(jù)庫(kù)2. MySQL (日期、天數(shù))轉(zhuǎn)換函數(shù)：to_days(date), from_days(days)
MYSQL數(shù)據(jù)庫(kù)select to_days('0000-00-00'); -- 0
select to_days('2008-08-08'); -- 733627
MYSQL數(shù)據(jù)庫(kù)select from_days(0);?????????? -- '0000-00-00'
select from_days(733627);????? -- '2008-08-08'
MYSQL數(shù)據(jù)庫(kù)3. MySQL Str to Date (字符串轉(zhuǎn)換為日期)函數(shù)：str_to_date(str, format)
MYSQL數(shù)據(jù)庫(kù)select str_to_date('08/09/2008', '%m/%d/%Y');?????????????????? -- 2008-08-09
select str_to_date('08/09/08' , '%m/%d/%y');?????????????????? -- 2008-08-09
select str_to_date('08.09.2008', '%m.%d.%Y');?????????????????? -- 2008-08-09
select str_to_date('08:09:30', '%h:%i:%s');???????????????????? -- 08:09:30
select str_to_date('08.09.2008 08:09:30', '%m.%d.%Y %h:%i:%s'); -- 2008-08-09 08:09:30
MYSQL數(shù)據(jù)庫(kù)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數(shù)據(jù)庫(kù)4. 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數(shù)據(jù)庫(kù)mysql> select date_format('2008-08-08 22:23:00', '%W %M %Y');
MYSQL數(shù)據(jù)庫(kù)+------------------------------------------------+
| date_format('2008-08-08 22:23:00', '%W %M %Y') |
+------------------------------------------------+
| Friday August 2008???????????????????????????? |
+------------------------------------------------+
MYSQL數(shù)據(jù)庫(kù)mysql> select date_format('2008-08-08 22:23:01', '%Y%m%d%H%i%s');
MYSQL數(shù)據(jù)庫(kù)+----------------------------------------------------+
| date_format('2008-08-08 22:23:01', '%Y%m%d%H%i%s') |
+----------------------------------------------------+
| 20080808222301???????????????????????????????????? |
+----------------------------------------------------+
MYSQL數(shù)據(jù)庫(kù)mysql> select time_format('22:23:01', '%H.%i.%s');
MYSQL數(shù)據(jù)庫(kù)+-------------------------------------+
| time_format('22:23:01', '%H.%i.%s') |
+-------------------------------------+
| 22.23.01??????????????????????????? |
+-------------------------------------+
MYSQL數(shù)據(jù)庫(kù)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數(shù)據(jù)庫(kù)5. MySQL 獲得國(guó)家地區(qū)時(shí)間格式函數(shù)：get_format()
MYSQL數(shù)據(jù)庫(kù)MySQL get_format() 語(yǔ)法：
MYSQL數(shù)據(jù)庫(kù)get_format(date|time|datetime, 'eur'|'usa'|'jis'|'iso'|'internal'
MYSQL數(shù)據(jù)庫(kù)MySQL get_format() 用法的全部示例：
MYSQL數(shù)據(jù)庫(kù)select get_format(date,'usa')????????? ;?? -- '%m.%d.%Y'
select get_format(date,'jis')????????? ;?? -- '%Y-%m-%d'
select get_format(date,'iso')????????? ;?? -- '%Y-%m-%d'
select get_format(date,'eur')????????? ;?? -- '%d.%m.%Y'
select get_format(date,'internal')???? ;?? -- '%Y%m%d'
select get_format(datetime,'usa')????? ;?? -- '%Y-%m-%d %H.%i.%s'
select get_format(datetime,'jis')????? ;?? -- '%Y-%m-%d %H:%i:%s'
select get_format(datetime,'iso')????? ;?? -- '%Y-%m-%d %H:%i:%s'
select get_format(datetime,'eur')????? ;?? -- '%Y-%m-%d %H.%i.%s'
select get_format(datetime,'internal') ;?? -- '%Y%m%d%H%i%s'
select get_format(time,'usa')????????? ;?? -- '%h:%i:%s %p'
select get_format(time,'jis')????????? ;?? -- '%H:%i:%s'
select get_format(time,'iso')????????? ;?? -- '%H:%i:%s'
select get_format(time,'eur')????????? ;?? -- '%H.%i.%s'
select get_format(time,'internal')???? ;?? -- '%H%i%s'
MYSQL數(shù)據(jù)庫(kù)MySQL get_format() 函數(shù)在實(shí)際中用到機(jī)會(huì)的比較少.
MYSQL數(shù)據(jù)庫(kù)6. MySQL 拼湊日期、時(shí)間函數(shù)：makdedate(year,dayofyear), maketime(hour,minute,second)
MYSQL數(shù)據(jù)庫(kù)select makedate(2001,31);?? -- '2001-01-31'
select makedate(2001,32);?? -- '2001-02-01'
MYSQL數(shù)據(jù)庫(kù)select maketime(12,15,30); -- '12:15:30'
MYSQL數(shù)據(jù)庫(kù)?
MYSQL數(shù)據(jù)庫(kù)
六、MySQL 時(shí)區(qū)(timezone)轉(zhuǎn)換函數(shù)
convert_tz(dt,from_tz,to_tz)
MYSQL數(shù)據(jù)庫(kù)select convert_tz('2008-08-08 12:00:00', '+08:00', '+00:00'); -- 2008-08-08 04:00:00
MYSQL數(shù)據(jù)庫(kù)時(shí)區(qū)轉(zhuǎn)換也可以通過(guò) date_add, date_sub, timestampadd 來(lái)實(shí)現(xiàn).
MYSQL數(shù)據(jù)庫(kù)select date_add('2008-08-08 12:00:00', interval -8 hour); -- 2008-08-08 04:00:00
select date_sub('2008-08-08 12:00:00', interval 8 hour); -- 2008-08-08 04:00:00
select timestampadd(hour, -8, '2008-08-08 12:00:00');????? -- 2008-08-08 04:00:00
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