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1¡£Sysdate µ±Ç°ÈÕÆÚºÍʱ¼ä SQL> Select sysdate from dual;
2¡£Last_day() ʱ¼äËùÔÚÔµÄ×îºóÒ»Ìì SQL> Select last_day(sysdate) from dual;
3¡£Add_months(d,n) µ±Ç°ÈÕÆÚdºóÍÆn¸öÔ ÓÃÓÚ´ÓÒ»¸öÈÕÆÚÖµÔö¼Ó»ò¼õÉÙһЩÔÂ·Ý          date_value:=add_months(date_value,number_of_months)
SQL> Select add_months(sysdate,2) from dual;
4¡£Months_between(f,s) ÈÕÆÚfºÍs¼äÏà²îÔÂÊý
SQL> select months_between(sysdate,to_date('2005-11-12','yyyy-mm-dd'))from dual;
5¡£NEXT_DAY(d, day_of_week) ·µ»ØÓÉ"day_of_week"ÃüÃûµÄ£¬ÔÚ±äÁ¿"d"Ö¸¶¨µÄÈÕÆÚÖ®ºóµÄµÚ¼¸¸ö¹¤×÷ÈÕµÄÈÕÆÚ ¡£²ÎÊý"day_of_week"±ØÐëΪ¸ÃÐÇÆÚÖеÄijһÌì¡£
SELECT next_day(to_date('20050620','YYYYMMDD'),1) from dual;
select next_day(sysdate,3) from dual;±íʾµÚÈý¹¤×÷ÈÕ,Íâ¹úµÚÒ»¸ö¹¤×÷ΪÖÜÈÕ¡£×¢ÒâÈç¹û½ñÌìÊÇÖÜÒ»£¬Ôò±íʾÕâÖܵÄÖܶþ£¬Èç¹ûÕâÖÜÖܶþÒѾ­¹ýÁË£¬Ôò±íʾÏÂÖܵÄÖܶþ
6¡£current_date()·µ»Øµ±Ç°»á»°Ê±ÇøÖеĵ±Ç°ÈÕÆÚ date_value:=current_date SQL> column sessiontimezone for a15 SQL> select sessiontimezone,current_date from dual;
SQL> alter session set time_zone='-11:00' 2 / »á»°ÒѸü¸Ä¡£ SQL> select sessiontimezone,current_timestamp from dual;
7¡£current_timestamp() ÒÔtimestamp with time zoneÊý¾ÝÀàÐÍ·µ»Øµ±Ç°»á»°Ê±ÇøÖеĵ±Ç°ÈÕÆÚ
SQL> select current_timestamp from dual;
8¡£dbtimezone()·µ»ØʱÇø SQL> select dbtimezone from dual;
9¡£extract()ÕÒ³öÈÕÆÚ»ò¼ä¸ôÖµµÄ×Ö¶ÎÖµ date_value:=extract(date_field from [datetime_value|interval_value])
SQL> select extract(month from sysdate) "This Month" from dual;
SQL> select extract(year from add_months(sysdate,36)) " Years" from dual;
     Years ----------       2008
10¡£localtimestamp()·µ»Ø»á»°ÖеÄ