增加或减去月份
SQL> select to_char(add_months(to_date(199912,yyyymm),2),yyyymm) from dual;
TO_CHA
------
200002
SQL> select to_char(add_months(to_date(199912,yyyymm),-2),yyyymm) from dual;
TO_CHA
------
199910
37.LAST_DAY
返回日期的最后一天
SQL> select to_char(sysdate,yyyy.mm.dd),to_char((sysdate)+1,yyyy.mm.dd) from dual;
TO_CHAR(SY TO_CHAR((S
---------- ----------
2004.05.09 2004.05.10
SQL> select last_day(sysdate) from dual;
LAST_DAY(S
----------
31-5月 -04
38.MONTHS_BETWEEN(date2,date1)
给出date2-date1的月份
SQL> select months_between(19-12月-1999,19-3月-1999) mon_between from dual;
MON_BETWEEN
-----------
9
SQL>selectmonths_between(to_date(2000.05.20,yyyy.mm.dd),to_date(2005.05.20,yyyy.mm.dd)) mon_betw from dual;
MON_BETW
---------
-60
39.NEW_TIME(date,this,that)
给出在this时区=other时区的日期和时间
SQL> select to_char(sysdate,yyyy.mm.dd hh24:mi:ss) bj_time,to_char(new_time
2 (sysdate,PDT,GMT),yyyy.mm.dd hh24:mi:ss) los_angles from dual;
BJ_TIME LOS_ANGLES
------------------- -------------------
2004.05.09 11:05:32 2004.05.09 18:05:32
40.NEXT_DAY(date,day)
给出日期date和星期x之后计算下一个星期的日期
SQL> select next_day('18-5月-2001','星期五') next_day from dual;
NEXT_DAY
----------
25-5月 -01
41.SYSDATE
用来得到系统的当前日期
SQL> select to_char(sysdate,dd-mm-yyyy day) from dual;
TO_CHAR(SYSDATE,
-----------------
09-05-2004 星期日
trunc(date,fmt)按照给出的要求将日期截断,如果fmt=mi表示保留分,截断秒
SQL> select to_char(trunc(sysdate,hh),yyyy.mm.dd hh24:mi:ss) hh,
2 to_char(trunc(sysdate,mi),yyyy.mm.dd hh24:mi:ss) hhmm from dual;
HH HHMM
------------------- -------------------
SQL> select to_char(add_months(to_date(199912,yyyymm),2),yyyymm) from dual;
TO_CHA
------
200002
SQL> select to_char(add_months(to_date(199912,yyyymm),-2),yyyymm) from dual;
TO_CHA
------
199910
37.LAST_DAY
返回日期的最后一天
SQL> select to_char(sysdate,yyyy.mm.dd),to_char((sysdate)+1,yyyy.mm.dd) from dual;
TO_CHAR(SY TO_CHAR((S
---------- ----------
2004.05.09 2004.05.10
SQL> select last_day(sysdate) from dual;
LAST_DAY(S
----------
31-5月 -04
38.MONTHS_BETWEEN(date2,date1)
给出date2-date1的月份
SQL> select months_between(19-12月-1999,19-3月-1999) mon_between from dual;
MON_BETWEEN
-----------
9
SQL>selectmonths_between(to_date(2000.05.20,yyyy.mm.dd),to_date(2005.05.20,yyyy.mm.dd)) mon_betw from dual;
MON_BETW
---------
-60
39.NEW_TIME(date,this,that)
给出在this时区=other时区的日期和时间
SQL> select to_char(sysdate,yyyy.mm.dd hh24:mi:ss) bj_time,to_char(new_time
2 (sysdate,PDT,GMT),yyyy.mm.dd hh24:mi:ss) los_angles from dual;
BJ_TIME LOS_ANGLES
------------------- -------------------
2004.05.09 11:05:32 2004.05.09 18:05:32
40.NEXT_DAY(date,day)
给出日期date和星期x之后计算下一个星期的日期
SQL> select next_day('18-5月-2001','星期五') next_day from dual;
NEXT_DAY
----------
25-5月 -01
41.SYSDATE
用来得到系统的当前日期
SQL> select to_char(sysdate,dd-mm-yyyy day) from dual;
TO_CHAR(SYSDATE,
-----------------
09-05-2004 星期日
trunc(date,fmt)按照给出的要求将日期截断,如果fmt=mi表示保留分,截断秒
SQL> select to_char(trunc(sysdate,hh),yyyy.mm.dd hh24:mi:ss) hh,
2 to_char(trunc(sysdate,mi),yyyy.mm.dd hh24:mi:ss) hhmm from dual;
HH HHMM
------------------- -------------------
2004.05.09 11:00:00 2004.05.09 11:17:00
本文转自 randy_shandong 51CTO博客，原文链接：http://blog.51cto.com/dba10g/417618，如需转载请自行联系原作者
![[Oracle]面试官：你举例几个内置函数，并且说说如何使用内置函数作正则匹配](https://ucc.alicdn.com/3mfxe2r26qbaq/developer-article1634560/20241106/3c985adba7754028bad691222250b227.jpeg?x-oss-process=image/resize,h_160,m_lfit)
