oracleÈÕÆÚ´¦ÀíÍêÈ«°æ(תÔØ)

TO_DATE¸ñʽ
Day:
dd number 12
dy abbreviated fri
day spelled out friday
ddspth spelled out, ordinal twelfth
Month:
mm number 03
mon abbreviated mar
month spelled out march
Year:
yy two digits 98
yyyy four digits 1998
24Сʱ¸ñʽÏÂʱ¼ä·¶Î§Îª£º 0:00:00 - 23:59:59....
12Сʱ¸ñʽÏÂʱ¼ä·¶Î§Îª£º 1:00:00 - 12:59:59 ....
1.
ÈÕÆÚºÍ×Ö·ûת»»º¯ÊýÓ÷¨£¨to_date,to_char£©
2.
select to_char( to_date(222,'J'),'Jsp') from dual
ÏÔʾTwo Hundred Twenty-Two
3.
ÇóijÌìÊÇÐÇÆÚ¼¸
select to_char(to_date('2002-08-26','yyyy-mm-dd'),'day') from dual;
ÐÇÆÚÒ»
select to_char(to_date('2002-08-26','yyyy-mm-dd'),'day','NLS_DATE_LANGUAGE = American') from dual;
monday
ÉèÖÃÈÕÆÚÓïÑÔ
ALTER SESSION SET NLS_DATE_LANGUAGE='AMERICAN';
Ò²¿ÉÒÔÕâÑù
TO_DATE ('2002-08-26', 'YYYY-mm-dd', 'NLS_DATE_LANGUAGE = American')
4.
Á½¸öÈÕÆÚ¼äµÄÌìÊý
select floor(sysdate - to_date('20020405','yyyymmdd')) from dual;
5. ʱ¼äΪnullµÄÓ÷¨
select id, active_date from table1
UNION
select 1, TO_DATE(null) from dual;
×¢ÒâÒªÓÃTO_DATE(null)
6.
a_date between to_date('20011201','yyyymmdd') and to_date('20011231','yyyymmdd')
ÄÇô12ÔÂ31ºÅÖÐÎç12µãÖ®ºóºÍ12ÔÂ1ºÅµÄ12µã֮ǰÊDz»°üº¬ÔÚÕâ¸ö·¶Î§Ö®Äڵġ£
ËùÒÔ£¬µ±Ê±¼äÐèÒª¾«È·µÄʱºò£¬¾õµÃto_char»¹ÊDZØÒªµÄ
7. ÈÕÆÚ¸ñʽ³åÍ»ÎÊÌâ
ÊäÈëµÄ¸ñʽҪ¿´Äã°²×°µÄORACLE×Ö·û¼¯µÄÀàÐÍ, ±ÈÈç: US7ASCII, date¸ñʽµÄÀàÐ;ÍÊÇ: '01-Jan-01'
alter system set NLS_DATE_LANGUAGE = American
alter session set NLS_DATE_LANGUAGE = American
»òÕßÔÚto_dateÖÐд
select to_char(to_date('2002-08-26','yyyy-mm-dd'),'day','NLS_DATE_LANGUAGE = American') from dual;
×¢ÒâÎÒÕâÖ»ÊǾÙÁËNLS_DATE_LANGUAGE£¬µ±È»»¹Óкܶ࣬
¿É²é¿´
select * from nls_session_parameters
select * from V$NLS_PARAMETERS
8.
select count(*)
from ( select rownum-1 rnum
from all_objects
where rownum <= to_date('2002-02-28','yyyy-mm-dd') - to_date('2002-
02-01','yyyy-mm-dd')+1
)
where to_char( to_date('2002-02-01','yyyy-mm-dd')+rnum-1, 'D' )
not
in ( '1', '7' )