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1¡£Sysdate µ±Ç°ÈÕÆÚºÍʱ¼ä
SQL> Select sysdate from dual;
SYSDATE
----------
21-6ÔÂ -05
2¡£Last_day ±¾ÔÂ×îºóÒ»Ìì
SQL> Select last_day(sysdate) from dual;
LAST_DAY(S
----------
30-6ÔÂ -05
3¡£Add_months(d,n) µ±Ç°ÈÕÆÚdºóÍÆn¸öÔÂ
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date_value:=add_months(date_value,number_of_months)
SQL> Select add_months(sysdate,2) from dual;
ADD_MONTHS
----------
21-8ÔÂ -05
4¡£Months_between(f,s) ÈÕÆÚfºÍs¼äÏà²îÔÂÊý
SQL> select months_between(sysdate,to_date('2005-11-12','yyyy-mm-dd'))from dual;
MONTHS_BETWEEN(SYSDATE,TO_DATE('2005-11-12','YYYY-MM-DD'))
----------------------------------------------------------
-4.6966741
5¡£NEXT_DAY(d, day_of_week)
·µ»ØÓÉ"day_of_week"ÃüÃûµÄ£¬ÔÚ±äÁ¿"d"Ö¸¶¨µÄÈÕÆÚÖ®ºóµÄµÚÒ»¸ö¹¤×÷ÈÕµÄÈÕÆÚ¡£²ÎÊý"day_of_week"±ØÐëΪ¸ÃÐÇÆÚÖеÄijһÌì¡£
SQL> SELECT next_day(to_date('20050620','YYYYMMDD'),1) from dual;
NEXT_DAY(T
----------
26-6ÔÂ -05
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;
SESSIONTIMEZONE CURRENT_DA
--------------- ----------
+08:00 13-11ÔÂ-03
SQL> alter session set time_zone='-11:00' 2 /
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SQL> select sessiontimezone,current_timestamp from dual;
SESSIONTIMEZONE CURRENT_TIMESTAMP
--------------- ------------------------------------
-11:00 12-11ÔÂ-03 04.59.13.668000 ÏÂÎç -11:00
7¡£current_timestamp()ÒÔtimestamp with time zoneÊý¾ÝÀàÐÍ·µ»Øµ±Ç°»á»°Ê±ÇøÖеĵ±Ç°ÈÕÆÚ
SQL> select current_timestamp from dual;
CURRENT_TIMESTAMP
---------------------------------------------------------------------------
21-6ÔÂ -05 10.13.08.220589 ÉÏÎç +08:00
8¡£dbtimezone()·µ»ØʱÇø
SQL> select dbtimezone from dual;
DBTIME
------
-08:00
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;
This Month
--------
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select event,sum(decode(wait_Time,0,0,1)) "Prev",
sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
from v$session_Wait
group by event order by 4;
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