在oracle中处理日期大全
1??
select months_between(to_date('02-01-1999','MM-DD-YYYY'),??
to_date('12-31-1998','MM-DD-YYYY')) "MONTHS" FROM DUAL;??
1.03225806451613??
10. Next_day的用法??
Next_day(date, day)??
Monday-Sunday, for format code DAY??
Mon-Sun, for format code DY??
1-7, for format code D??
11??
select 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 is??
begin??
return sysdate;??
end;??
select to_char(sys_date,'hh:mi:ss') from all_objects;??
12.??
获得小时数??
SELECT EXTRACT(HOUR FROM TIMESTAMP '2001-02-16 2:38:40') from offer??
SQL> select sysdate ,to_char(sysdate,'hh') from dual;??
SYSDATE TO_CHAR(SYSDATE,'HH')??
-------------------- ---------------------??
2003-10-13 19:35:21 07??
SQL> select sysdate ,to_char(sysdate,'hh24') from dual;??
SYSDATE TO_CHAR(SYSDATE,'HH24')??
-------------------- -----------------------??
2003-10-13 19:35:21 19??
获取年月日与此类似??
13.??
年月日的处理??
select older_date,??
newer_date,??
years,??
months,??
abs(??
trunc(??
newer_date-??
add_months( older_date,years*12+months )??
)??
) days??
from ( select??
trunc(months_between( newer_date, older_date )/12) YEARS,??
mod(trunc(months_between( newer_date, older_date )),??
12 ) MONTHS,??
newer_date,??
older_date??
from ( select hiredate older_date,??
add_months(hiredate,rownum)+rownum newer_date??
from emp )??
)??
14.??
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 dual??
16.??
找出今年的天数??
select add_months(trunc(sysdate,'year'), 12) - trunc(sysdate,'year') from dual??
闰年的处理方法??
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 0099??
rrrr 99 1999??
yyyy 01 0001??
rrrr 01 2001??
18.不同时区的处理??
select to_char( NEW_TIME( sysdate, 'GMT','EST'), 'dd/mm/yyyy hh:mi:ss') ,sysdate??
from dual;??
19.??
5秒钟一个间隔??
Select TO_DATE(FLOOR(TO_CHAR(sysdate,'SSSSS')/300) * 300,'SSSSS') ,TO_CHAR(sysdate,'SSSSS')??
from dual??
2002-11-1 9:55:00 35786??
SSSSS表示5位秒数??
20.??
一年的第几天??
select TO_CHAR(SYSDATE,'DDD'),sysdate from dual??
310 2002-11-6 10:03:51??
21.计算小时,分,秒,毫秒??
select??
Days,??
A,??
TRUNC(A*24) Hours,??
TRUNC(A*24*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)) mSeconds??
from??
(??
select??
trunc(sysdate) Days,??
sysdate - trunc(sysdate) A??
from dual??
)??
select * from tabname??
order by decode(mode,'FIFO',1,-1)*to_char(rq,'yyyymmddhh24miss');??
//??
floor((date2-date1) /365) 作为年??
floor((date2-date1, 365) /30) 作为月??
mod(mod(date2-date1, 365), 30)作为日.??
23.next_day函数??
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
===================================
在oracle中有很多关于日期的函数，如：
1、add_months()用于从一个日期值增加或减少一些月份
date_value:=add_months(date_value,number_of_months)
例：
SQL> select add_months(sysdate,12) "Next Year" from dual;
Next Year
----------
13-11月-04
SQL> select add_months(sysdate,112) "Last Year" from dual;
Last Year
----------
13-3月 -13
SQL>
2、current_date()返回当前会放时区中的当前日期
date_value:=current_date
SQL> column sessiontimezone for a15
SQL> select sessiontimezone,current_date from dual;
SESSIONTIMEZONE CURRENT_DA
--------------- ----------
+08:00 13-11月-03
SQL> alter session set time_zone='-11:00'
?? 2 /
会话已更改。
SQL> select sessiontimezone,current_timestamp from dual;
SESSIONTIMEZONE CURRENT_TIMESTAMP
--------------- ------------------------------------
-11:00 12-11月-03 04.59.13.668000 下午 -11:
???????????????? 00
SQL>
3、current_timestamp()以timestamp with time zone数据类型返回当前会放时区中的当前日期
timestamp_with_time_zone_value:=current_timestamp([timestamp_precision])
SQL> column sessiontimezone for a15
SQL> column current_timestamp format a36
SQL> select sessiontimezone,current_timestamp from dual;
SESSIONTIMEZONE CURRENT_TIMESTAMP
--------------- ------------------------------------
+08:00 13-11月-03 11.56.28.160000 上午 +08:
???????????????? 00
SQL> alter session set time_zone='-11:00'
?? 2 /
会话已更改。
SQL> select sessiontimezone,current_timestamp from dual;
SESSIONTIMEZONE CURRENT_TIMESTAMP
--------------- ------------------------------------
-11:00 12-11月-03 04.58.00.243000 下午 -11:
???????????????? 00
SQL>
4、dbtimezone()返回时区
varchar_value:=dbtimezone
SQL> select dbtimezone from dual;
DBTIME
------
-07:00
SQL>
5、extract()找出日期或间隔值的字段值
date_value:=extract(date_field from [datetime_value|interval_value])
SQL> select extract(month from sysdate) "This Month" from dual;
This Month
----------
???????? 11
SQL> select extract(year from add_months(sysdate,36)) "3 Years Out" from dual;
3 Years Out
-----------
??????? 2006
SQL>
6、last_day()返回包含了日期参数的月份的最后一天的日期
date_value:=last_day(date_value)
SQL> select last_day(date'2000-02-01') "Leap Yr?" from dual;
Leap Yr?
----------
29-2月 -00
SQL> select last_day(sysdate) "Last day of this month" from dual;
Last day o
----------
30-11月-03
SQL>
7、localtimestamp()返回会话中的日期和时间
timestamp_value:=localtimestamp
SQL> column localtimestamp format a28
SQL> select localtimestamp from dual;
LOCALTIMESTAMP
----------------------------
13-11月-03 12.09.15.433000
下午
SQL> select localtimestamp,current_timestamp from dual;
LOCALTIMESTAMP CURRENT_TIMESTAMP
---------------------------- ------------------------------------
13-11月-03 12.09.31.006000 13-11月-03 12.09.31.006000 下午 +08:
下午 00
SQL> alter session set time_zone='-11:00';
会话已更改。
SQL> select localtimestamp,to_char(sysdate,'DD-MM-YYYY HH:MI:SS AM') "SYSDATE" from dual;
LOCALTIMESTAMP SYSDATE
---------------------------- ------------------------
12-11月-03 05.11.31.259000 13-11-2003 12:11:31 下午
下午
SQL>
8、months_between()判断两个日期之间的月份数量
number_value:=months_between(date_value,date_value)
SQL> select months_between(sysdate,date'1971-05-18') from dual;
MONTHS_BETWEEN(SYSDATE,DATE'1971-05-18')
----------------------------------------
?????????????????????????????? 389.855143
SQL> select months_between(sysdate,date'2001-01-01') from dual;
MONTHS_BETWEEN(SYSDATE,DATE'2001-01-01')
----------------------------------------
?????????????????????????????? 34.4035409
SQL>
9、next_day()给定一个日期值，返回由第二个参数指出的日子第一次出现在的日期值（应返回相应日子的名称字符串）
==============================================
1.查询某周的第一天
select trunc(decode(ww, 53, to_date(yy || '3112', 'yyyyddmm'), to_date(yy || '-' || to_char(ww * 7), 'yyyy-ddd')), 'd') last_day
from (select substr('2004-32', 1, 4) yy, to_number(substr('2004-32', 6)) ww
????????? from dual)
select trunc(to_date(substr('2003-01',1,5)||to_char((to_number(substr('2003-01',6)))*7),'yyyy-ddd'),'d')-6 first_day from dual
select min(v_date) from
?? (select (to_date('200201','yyyymm') + rownum) v_date
?? from all_tables
?? where rownum < 370)
where to_char(v_date,'yyyy-iw') = '2002-49'
2.查询某周的最后一天
select trunc(decode(ww, 53, to_date(yy || '3112', 'yyyyddmm'), to_date(yy || '-' || to_char(ww * 7), 'yyyy-ddd')), 'd') - 6 first_day
?? from (select substr('2004-33', 1, 4) yy, to_number(substr('2004-33', 6)) ww
?????????? from dual)
??????????
select trunc(to_date(substr('2003-01',1,5)||to_char((to_number(substr('2003-01',6)))*7),'yyyy-ddd'),'d') last_day from dual
select max(v_date) from
?? (select (to_date('200408','yyyymm') + rownum) v_date
?? from all_tables
?? where rownum < 370)
where to_char(v_date,'yyyy-iw') = '2004-33'
3.查询某周的日期
select min_date, to_char(min_date,'day') day from
(select to_date(substr('2004-33',1,4)||'001'+rownum-1,'yyyyddd') min_date
???????? from all_tables
?? where rownum <= decode(mod(to_number(substr('2004-33',1,4)),4),0,366,365)??
?? union
?? select to_date(substr('2004-33',1,4)-1||
????????? decode(mod(to_number(substr('2004-33',1,4))-1,4),0,359,358)+rownum,'yyyyddd') min_date
???????? from all_tables??????????
?????????? where rownum <= 7
?? union
?? select to_date(substr('2004-33',1,4)+1||'001'+rownum-1,'yyyyddd') min_date
???????? from all_tables??????????
?????????? where rownum <= 7???????????????????????
)
where to_char(min_date,'yyyy-iw') ='2004-33'
=============================================
在论坛中常常看到有对oracle中时间运算提问的问题，今天有时间，看了看以前各位兄弟的贴子，整理了一下，并作了个示例，希望会对大家有帮助。
首先感谢ern、eric.li及各版主还有热心的兄弟们
内容如下：
1、oracle支持对日期进行运算
2、日期运算时是以天为单位进行的
3、当需要以分秒等更小的单位算值时，按时间进制进行转换即可
4、进行时间进制转换时注意加括号（见示例中红色括号），否则会出问题
SQL> alter session set nls_date_format='yyyy-mm-dd hh:mi:ss';
会话已更改。
SQL> set serverout on
SQL> declare
?? 2 DateValue date;
?? 3 begin
?? 4 select sysdate into DateValue from dual;
?? 5 dbms_output.put_line('源时间:'||to_char(DateValue));
?? 6 dbms_output.put_line('源时间减1天:'||to_char(DateValue-1));
?? 7 dbms_output.put_line('源时间减1天1小时:'||to_char(DateValue-1-1/24));
?? 8 dbms_output.put_line('源时间减1天1小时1分:'||to_char(DateValue-1-1/24-1/(24*60)));
?? 9 dbms_output.put_line('源时间减1天1小时1分1秒:'||to_char(DateValue-1-1/24-1/(24*60)-1/(24*60*6
0)));
10 end;
11 /
源时间:2003-12-29 11:53:41
源时间减1天:2003-12-28 11:53:41
源时间减1天1小时:2003-12-28 10:53:41
源时间减1天1小时1分:2003-12-28 10:52:41
源时间减1天1小时1分1秒:2003-12-28 10:52:40
PL/SQL 过程已成功完成。