ORAcle 日期时间函数大全

1、TO_DATE格式(以时间:2007-11-02 13:45:25为例Year:yy two digits 两位年显示值:07yyy three digits 三位年显示值:007yyyy four digits 四位年显示值:2007Month:mm number 两位月显示值:11mon abbreviated 字符集表示显示值:11月,若是英文版,显示nov month spelled out 字符集表示显示值:11月,若是英文版,显示novemberDay:dd number 当月第几天显示值:02ddd number 当年第几天显示值:02dy abbreviated 当周第几天简写

2、显示值:星期五,若是英文版,显示fri day spelled out 当周第几天全写显示值:星期五,若是英文版,显示fridayddspth spelled out, ordinal twelfthHour:hh two digits 12小时进制显示值:01hh24 two digits 24小时进制显示值:13Minute:mi two digits 60进制显示值:45Second:ss two digits 60进制显示值:25其它Q digit 季度显示值:4WW digit 当年第几周显示值:44W digit 当月第几周显示值:124小时格式下时间范围为: 0:00:00 -

3、23:59:59.12小时格式下时间范围为: 1:00:00 - 12:59:59 .1. 日期和字符转换函数用法(to_date,to_charselect to_char(sysdate,'yyyy-mm-dd hh24:mi:ss' as nowTime from dual; /日期转化为字符串select to_char(sysdate,'yyyy' as nowYear from dual; /获取时间的年select to_char(sysdate,'mm' as nowMonth from dual; /获取时间的月select t

4、o_char(sysdate,'dd' as nowDay from dual; /获取时间的日select to_char(sysdate,'hh24' as nowHour from dual; /获取时间的时select to_char(sysdate,'mi' as nowMinute from dual; /获取时间的分select to_char(sysdate,'ss' as nowSecond from dual; /获取时间的秒select to_date('2004-05-07 13:23:44'

5、;,'yyyy-mm-dd hh24:mi:ss' from dual/2.select to_char( to_date(222,'J','Jsp' from dual显示Two Hundred Twenty-Two3.求某天是星期几select to_char(to_date('2002-08-26','yyyy-mm-dd','day' from dual;星期一select to_char(to_date('2002-08-26','yyyy-mm-dd',&

6、#39;day','NLS_DATE_LANGUAGE = American' from dual;monday设置日期语言ALTER SESSION SET NLS_DATE_LANGUAGE='AMERICAN'也可以这样TO_DATE ('2002-08-26', 'YYYY-mm-dd', 'NLS_DATE_LANGUAGE = American'4. 两个日期间的天数select floor(sysdate - to_date('20020405','yyyymmdd&#

7、39; from dual;5. 时间为null的用法select id, active_date from table1UNIONselect 1, TO_DATE(null from dual;注意要用TO_DATE(null6.月份差a_date between to_date('20011201','yyyymmdd' and to_date('20011231','yyyymmdd'那么12月31号中午12点之后和12月1号的12点之前是不包含在这个范围之内的。所以,当时间需要精确的时候,觉得to_char还是必要的7.

8、 日期格式冲突问题输入的格式要看你安装的ORACLE字符集的类型, 比如: US7ASCII, date格式的类型就是:'01-Jan-01'alter system set NLS_DATE_LANGUAGE = Americanalter session set NLS_DATE_LANGUAGE = American或者在to_date中写select to_char(to_date('2002-08-26','yyyy-mm-dd','day','NLS_DATE_LANGUAGE = American'

9、from dual;注意我这只是举了NLS_DATE_LANGUAGE,当然还有很多,可查看select * from nls_session_parametersselect * from V$NLS_PARAMETERS8.select count(*from ( select rownum-1 rnumfrom all_objectswhere rownum <= to_date('2002-02-28','yyyy-mm-dd' - to_date('2002-02-01','yyyy-mm-dd'+1where t

10、o_char( to_date('2002-02-01','yyyy-mm-dd'+rnum-1, 'D' not in ( '1', '7' 查找2002-02-28至2002-02-01间除星期一和七的天数在前后分别调用DBMS_UTILITY.GET_TIME, 让后将结果相减(得到的是1/100秒, 而不是毫秒.9. 查找月份select months_between(to_date('01-31-1999','MM-DD-YYYY',to_date('12-31-1

11、998','MM-DD-YYYY' "MONTHS" FROM DUAL;1select months_between(to_date('02-01-1999','MM-DD-YYYY',to_date('12-31-1998','MM-DD-YYYY' "MONTHS" FROM DUAL;1.0322580645161310. Next_day的用法Next_day(date, dayMonday-Sunday, for format code DAYMon-Su

12、n, for format code DY1-7, for format code D11select to_char(sysdate,'hh:mi:ss' TIME from all_objects注意:第一条记录的TIME 与最后一行是一样的可以建立一个函数来处理这个问题create or replace function sys_date return date isbeginreturn sysdate;end;select to_char(sys_date,'hh:mi:ss' from all_objects;12.获得小时数extract(找出日期

13、或间隔值的字段值SELECT EXTRACT(HOUR FROM TIMESTAMP '2001-02-16 2:38:40' from offerSQL> select sysdate ,to_char(sysdate,'hh' from dual;SYSDATE TO_CHAR(SYSDATE,'HH'- -2003-10-13 19:35:21 07SQL> select sysdate ,to_char(sysdate,'hh24' from dual;SYSDATE TO_CHAR(SYSDATE,'

14、HH24'- -2003-10-13 19:35:21 1913.年月日的处理select older_date,newer_date,years,months,abs(trunc(newer_date-add_months( older_date,years*12+months daysfrom ( selecttrunc(months_between( newer_date, older_date /12 YEARS,mod(trunc(months_between( newer_date, older_date ,12 MONTHS,newer_date,older_datefr

15、om (select hiredate older_date, add_months(hiredate,rownum+rownum newer_datefrom emp14.处理月份天数不定的办法select to_char(add_months(last_day(sysdate +1, -2, 'yyyymmdd',last_day(sysdate from dual16.找出今年的天数select add_months(trunc(sysdate,'year', 12 - trunc(sysdate,'year' from dual闰年的处理

16、方法to_char( last_day( to_date('02' | | :year,'mmyyyy' , 'dd' 如果是28就不是闰年17.yyyy与rrrr的区别'YYYY99 TO_C- -yyyy 99 0099rrrr 99 1999yyyy 01 0001rrrr 01 200118.不同时区的处理select to_char( NEW_TIME( sysdate, 'GMT','EST', 'dd/mm/yyyy hh:mi:ss' ,sysdatefrom dual;19

17、.5秒钟一个间隔Select TO_DATE(FLOOR(TO_CHAR(sysdate,'SSSSS'/300 * 300,'SSSSS' ,TO_CHAR(sysdate,'SSSSS'from dual2002-11-1 9:55:00 35786SSSSS表示5位秒数20.一年的第几天select TO_CHAR(SYSDATE,'DDD',sysdate from dual310 2002-11-6 10:03:5121.计算小时,分,秒,毫秒selectDays,A,TRUNC(A*24 Hours,TRUNC(A*2

18、4*60 - 60*TRUNC(A*24 Minutes,TRUNC(A*24*60*60 - 60*TRUNC(A*24*60 Seconds,TRUNC(A*24*60*60*100 - 100*TRUNC(A*24*60*60 mSecondsfrom(selecttrunc(sysdate Days,sysdate - trunc(sysdate Afrom dualselect * from tabnameorder by decode(mode,'FIFO',1,-1*to_char(rq,'yyyymmddhh24miss'/floor(date2

19、-date1 /365 作为年floor(date2-date1, 365 /30 作为月d(mod(date2-date1, 365, 30作为日.23.next_day函数返回下个星期的日期,day为1-7或星期日-星期六,1表示星期日next_day(sysdate,6是从当前开始下一个星期五。后面的数字是从星期日开始算起。1 2 3 4 5 6 7日一二三四五六-select (sysdate-to_date('2003-12-03 12:55:45','yyyy-mm-dd hh24:mi:ss'*24*60*60 from ddual日期返回的是天然

20、后转换为ss24,round舍入到最接近的日期(day:舍入到最接近的星期日select sysdate S1,round(sysdate S2 ,round(sysdate,'year' YEAR,round(sysdate,'month' MONTH ,round(sysdate,'day' DAY from dual25,trunc截断到最接近的日期,单位为天 ,返回的是日期类型select sysdate S1,trunc(sysdate S2, /返回当前日期,无时分秒trunc(sysdate,'year' YEAR,

21、 /返回当前年的1月1日,无时分秒trunc(sysdate,'month' MONTH , /返回当前月的1日,无时分秒trunc(sysdate,'day' DAY /返回当前星期的星期天,无时分秒from dual26,返回日期列表中最晚日期select greatest('01-1月-04','04-1月-04','10-2月-04' from dual27.计算时间差注:oracle时间差是以天数为单位,所以换算成年月,日select floor(to_number(sysdate-to_date(

22、9;2007-11-02 15:55:03','yyyy-mm-dd hh24:mi:ss'/365 as spanYears from dual /时间差-年select ceil(moths_between(sysdate-to_date('2007-11-02 15:55:03','yyyy-mm-dd hh24:mi:ss' as spanMonths from dual /时间差-月select floor(to_number(sysdate-to_date('2007-11-02 15:55:03','

23、yyyy-mm-dd hh24:mi:ss' as spanDays from dual /时间差-天select floor(to_number(sysdate-to_date('2007-11-02 15:55:03','yyyy-mm-dd hh24:mi:ss'*24 as spanHours from dual /时间差-时select floor(to_number(sysdate-to_date('2007-11-02 15:55:03','yyyy-mm-dd hh24:mi:ss'*24*60 as sp

24、anMinutes from dual /时间差-分select floor(to_number(sysdate-to_date('2007-11-02 15:55:03','yyyy-mm-dd hh24:mi:ss'*24*60*60 as spanSeconds from dual /时间差-秒28.更新时间注:oracle时间加减是以天数为单位,设改变量为n,所以换算成年月,日select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss',to_char(sysdate+n*365,'yyyy-mm-

25、dd hh24:mi:ss' as newTime from dual /改变时间-年select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss',add_months(sysdate,n as newTime from dual /改变时间-月select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss',to_char(sysdate+n,'yyyy-mm-dd hh24:mi:ss' as newTime from dual /改变时间-日select to_char(s

26、ysdate,'yyyy-mm-dd hh24:mi:ss',to_char(sysdate+n/24,'yyyy-mm-dd hh24:mi:ss' as newTime from dual /改变时间-时select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss',to_char(sysdate+n/24/60,'yyyy-mm-dd hh24:mi:ss' as newTime from dual /改变时间-分select to_char(sysdate,'yyyy-mm-dd hh

27、24:mi:ss',to_char(sysdate+n/24/60/60,'yyyy-mm-dd hh24:mi:ss' as newTime from dual /改变时间-秒29.查找月的第一天,最后一天SELECT Trunc(Trunc(SYSDATE, 'MONTH' - 1, 'MONTH' First_Day_Last_Month,Trunc(SYSDATE, 'MONTH' - 1 / 86400 Last_Day_Last_Month,Trunc(SYSDATE, 'MONTH' Firs

28、t_Day_Cur_Month,LAST_DAY(Trunc(SYSDATE, 'MONTH' + 1 - 1 / 86400 Last_Day_Cur_Month FROM dual;三. 字符函数(可用于字面字符或数据库列1,字符串截取select substr('abcdef',1,3 from dual2,查找子串位置select instr('abcfdgfdhd','fd' from dual3,字符串连接select 'HELLO'|'hello world' from dual;4,

29、 1去掉字符串中的空格select ltrim(' abc' s1,rtrim('zhang ' s2,trim(' zhang ' s3 from dual2去掉前导和后缀select trim(leading 9 from 9998767999 s1,trim(trailing 9 from 9998767999 s2,trim(9 from 9998767999 s3 from dual;5,返回字符串首字母的Ascii值select ascii('a' from dual6,返回ascii值对应的字母select chr(

30、97 from dual7,计算字符串长度select length('abcdef' from dual8,initcap(首字母变大写 ,lower(变小写,upper(变大写select lower('ABC' s1,upper('def' s2,initcap('efg' s3from dual;9,Replaceselect replace('abc','b','xy' from dual;10,translateselect translate('abc'

31、,'b','xx' from dual; - x是1位11,lpad 左添充 rpad 右填充(用于控制输出格式select lpad('func',15,'=' s1, rpad('func',15,'-' s2 from dual;select lpad(dname,14,'=' from dept;12, decode实现if .then 逻辑 注:第一个是表达式,最后一个是不满足任何一个条件的值 select deptno,decode(deptno,10,'1

32、9;,20,'2',30,'3','其他' from dept;例:select seed,account_name,decode(seed,111,1000,200,2000,0 from t_userInfo/如果seed为111,则取1000;为200,取2000;其它取0select seed,account_name,decode(sign(seed-111,1,'big seed',-1,'little seed','equal seed' from t_userInfo/如果seed&

33、gt;111,则显示大;为200,则显示小;其它则显示相等13 case实现switch .case 逻辑SELECT CASE X-FIELDWHEN X-FIELD < 40 THEN 'X-FIELD 小于 40'WHEN X-FIELD < 50 THEN 'X-FIELD 小于 50'WHEN X-FIELD < 60 THEN 'X-FIELD 小于 60'ELSE 'UNBEKNOWN'ENDFROM DUAL注:CASE语句在处理类似问题就显得非常灵活。当只是需要匹配少量数值时,用Decode更为

34、简洁。四.数字函数1,取整函数(ceil 向上取整,floor 向下取整select ceil(66.6 N1,floor(66.6 N2 from dual;2, 取幂(power 和求平方根(sqrtselect power(3,2 N1,sqrt(9 N2 from dual;3,求余select mod(9,5 from dual;4,返回固定小数位数 (round:四舍五入,trunc:直接截断select round(66.667,2 N1,trunc(66.667,2 N2 from dual;5,返回值的符号(正数返回为1,负数为-1select sign(-32,sign(2

35、93 from dual;五.转换函数1,to_char(将日期和数字类型转换成字符类型1 select to_char(sysdate s1,to_char(sysdate,'yyyy-mm-dd' s2,to_char(sysdate,'yyyy' s3,to_char(sysdate,'yyyy-mm-dd hh12:mi:ss' s4,to_char(sysdate, 'hh24:mi:ss' s5,to_char(sysdate,'DAY' s6from dual;2 select sal,to_char

36、(sal,'$99999' n1,to_char(sal,'$99,999' n2 from emp2, to_date(将字符类型转换为日期类型insert into emp(empno,hiredate values(8000,to_date('2004-10-10','yyyy-mm-dd'3, to_number( 转换为数字类型select to_number(to_char(sysdate,'hh12' from dual; /以数字显示的小时数六.其他函数1.user:返回登录的用户名称select

37、user from dual;2.vsize:返回表达式所需的字节数select vsize('HELLO' from dual;3.nvl(ex1,ex2:ex1值为空则返回ex2,否则返回该值本身ex1(常用例:如果雇员没有佣金,将显示0,否则显示佣金select comm,nvl(comm,0 from emp;4.nullif(ex1,ex2:值相等返空,否则返回第一个值例:如果工资和佣金相等,则显示空,否则显示工资select nullif(sal,comm,sal,comm from emp;5.coalesce:返回列表中第一个非空表达式select comm,sal,coalesce(comm,sal,sal*10 from emp;6.nvl2(ex1,ex2,ex3 :如果ex1不为空,显示ex2,否则显示ex3如:查看有佣金的雇员姓名以及他们的佣金select nvl2(comm,ename,' as HaveCommName,comm from emp;七.分组函数max min avg count sum 1，整个结果集是一个组 1 求部门 30 的最高工资，最低工资,平均工资，总人数，有工作的人数，工种数量及工资 总和 select max(e