OracleÈÕÆÚº¯Êý¼¯½õ(¶þ)

OracleÈÕÆÚº¯Êý¼¯½õ(¶þ)
¶þ¡¢³£ÓÃʱ¼äº¯Êý
1.trunc(sysdate,'Q') ±¾¼¾¶ÈµÚÒ»Ìì
SQL> select trunc(sysdate,'Q') from dual;
TRUNC(SYSDATE,'Q')
------------------
2007-4-1
2.trunc(sysdate,'D') ±¾ÖܵĵÚÒ»Ìì(ÖÜÈÕ)
SQL> select trunc(sysdate,'D')from dual;
TRUNC(SYSDATE,'D')
------------------
2007-5-27
3.last_day(sysdate) ±¾ÔÂ×îºóÒ»Ìì
SQL> select last_day(sysdate) from dual;
LAST_DAY(SYSDATE)
-----------------
2007-5-31 15:20:3
4.add_months(sysdate,2) ÈÕÆÚsysdateºóÍÆ2¸öÔÂ
SQL> select add_months(sysdate,2) from dual;
ADD_MONTHS(SYSDATE,2)
---------------------
2007-7-29 15:21:14
5.next_day(sysdate,2) ÈÕÆÚsysdateÖ®ºóµÄµÚÒ»ÖÜÖÐ,µÚ2(Ö¸¶¨ÐÇÆڵĵڼ¸Ìì)ÊÇʲôÈÕÆÚ
SQL> select next_day(sysdate,2) from dual;
NEXT_DAY(SYSDATE,2)
-------------------
2007-6-4 15:22:10
6.Months_between(f,s) ÈÕÆÚfºÍs¼äÏà²îÔÂÊý
SQL> select months_between(sysdate,to_date('2007-04-12','yyyy-mm-dd'))from dual;
MONTHS_BETWEEN(SYSDATE,TO_DATE
------------------------------
1.56909908900836
7.µÃµ½SYSDATE+5ËùÔÚµÄÔ·Ý
SQL> SELECT to_char(SYSDATE+5,'mon','nls_date_language=american') from dual;
TO_CHAR(SYSDATE+5,'MON','NLS_D
------------------------------
jun
8.current_date()·µ»Øµ±Ç°»á»°Ê±ÇøÖеĵ±Ç°ÈÕÆÚ¡£
9.select dbtimezone from dual;
10.extract()ÕÒ³öÈÕÆÚ»ò¼ä¸ôÖµµÄ×Ö¶ÎÖµ
SQL> select extract(month from sysdate) "This Month" from dual;
This Month
----------
5
SQL> select extract(year from sysdate) "This year" from dual;
This year
----------
2007
SQL> select extract(month from add_months(sysdate,2)) " Month" from dual;
Month
----------
7
==================================================================