ORACLE 常用函數總結(80個)第1/2頁

1. ASCII
返回與指定的字元對應的十進位數;
SQL> select ascii(A) A,ascii(a) a,ascii(0) zero,ascii( ) space from dual;
A A ZERO SPACE
--------- --------- --------- ---------
65 97 48 32

2. CHR
給出整數,返回對應的字元;
SQL> select chr(54740) zhao,chr(65) chr65 from dual;
ZH C
-- -
趙 A
3. CONCAT
串連兩個字串;
SQL> select concat(010-,88888888)||轉23 高乾競電話 from dual;
高乾競電話
----------------
010-88888888轉23
4. INITCAP
返回字串並將字串的第一個字母變為大寫;
SQL> select initcap(smith) upp from dual;
UPP
-----
Smith

5.INSTR(C1,C2,I,J)
在一個字串中搜尋指定的字元,返回傳現指定的字元的位置;
C1 被搜尋的字串
C2 希望搜尋的字串
I 搜尋的開始位置,預設為1
J 出現的位置,預設為1
SQL> select instr(oracle traning,ra,1,2) instring from dual;
INSTRING
---------
9

6.LENGTH
返回字串的長度;
SQL> select name,length(name),addr,length(addr),sal,length(to_char(sal)) from gao.nchar_tst;
NAME LENGTH(NAME) ADDR LENGTH(ADDR) SAL LENGTH(TO_CHAR(SAL))
------ ------------ ---------------- ------------ --------- --------------------
高乾競 3 北京市海錠區 6 9999.99 7

7.LOWER
返回字串,並將所有的字元小寫
SQL> select lower(AaBbCcDd)AaBbCcDd from dual;
AABBCCDD
--------
aabbccdd

8.UPPER
返回字串,並將所有的字元大寫
SQL> select upper(AaBbCcDd) upper from dual;
UPPER
--------
AABBCCDD

9.RPAD和LPAD(粘貼字元)
RPAD 在列的右邊粘貼字元
LPAD 在列的左邊粘貼字元
SQL> select lpad(rpad(gao,10,*),17,*)from dual;
LPAD(RPAD(GAO,1
-----------------
*******gao*******
不夠字元則用*來填滿

10.LTRIM和RTRIM
LTRIM 刪除左邊出現的字串
RTRIM 刪除右邊出現的字串
SQL> select ltrim(rtrim( gao qian jing , ), ) from dual;
LTRIM(RTRIM(
-------------
gao qian jing

11.SUBSTR(string,start,count)
取子字串,從start開始,取count個
SQL> select substr(13088888888,3,8) from dual;
SUBSTR(
--------
08888888

12.REPLACE(string,s1,s2)
string 希望被替換的字元或變數
s1 被替換的字串
s2 要替換的字串
SQL> select replace(he love you,he,i) from dual;
REPLACE(H
----------
i love you

13.SOUNDEX
返回一個與給定的字串讀音相同的字串
SQL> create table table1(xm varchar(8));
SQL> insert into table1 values(weather);
SQL> insert into table1 values(wether);
SQL> insert into table1 values(gao);
SQL> select xm from table1 where soundex(xm)=soundex(weather);
XM
--------
weather
wether
? 14.TRIM(s from string)
LEADING 剪掉前面的字元
TRAILING 剪掉後面的字元
如果不指定,預設為空白格符
15.ABS
返回指定值的絕對值
SQL> select abs(100),abs(-100) from dual;
ABS(100) ABS(-100)
--------- ---------
100 100

19.CEIL
返回大於或等於給出數位最小整數
SQL> select ceil(3.1415927) from dual;
CEIL(3.1415927)
---------------
4

22.EXP
返回一個數字e的n次方根
SQL> select exp(2),exp(1) from dual;
EXP(2) EXP(1)
--------- ---------
7.3890561 2.7182818

23.FLOOR
對給定的數字取整數
SQL> select floor(2345.67) from dual;
FLOOR(2345.67)
--------------
2345

26.MOD(n1,n2)
返回一個n1除以n2的餘數
SQL> select mod(10,3),mod(3,3),mod(2,3) from dual;
MOD(10,3) MOD(3,3) MOD(2,3)
--------- --------- ---------
1 0 2

27.POWER
返回n1的n2次方根
SQL> select power(2,10),power(3,3) from dual;
POWER(2,10) POWER(3,3)
----------- ----------
1024 27

28.ROUND和TRUNC
按照指定的精度進行舍入
SQL> select round(55.5),round(-55.4),trunc(55.5),trunc(-55.5) from dual;
ROUND(55.5) ROUND(-55.4) TRUNC(55.5) TRUNC(-55.5)
----------- ------------ ----------- ------------
56 -55 55 -55

29.SIGN
取數字n的符號,大於0返回1,小於0返回-1,等於0返回0
SQL> select sign(123),sign(-100),sign(0) from dual;
SIGN(123) SIGN(-100) SIGN(0)
--------- ---------- ---------
1 -1 0

36.ADD_MONTHS
增加或減去月份
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
返回日期的最後一天
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)
給出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)
給出在this時區=other時區的日期和時間
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)
給出日期date和星期x之後計算下一個星期的日期
SQL> select next_day('18-5月-2001','星期五') next_day from dual;
NEXT_DAY
----------
25-5月 -01

41.SYSDATE
用來得到系統的當前日期
SQL> select to_char(sysdate,dd-mm-yyyy day) from dual;
TO_CHAR(SYSDATE,
-----------------
09-05-2004 星期日
trunc(date,fmt)按照給出的要求將日期截斷,如果fmt=mi表示保留分,截斷秒
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

42.CHARTOROWID
將字元資料類型轉換為ROWID類型
SQL> select rowid,rowidtochar(rowid),ename from scott.emp;
ROWID ROWIDTOCHAR(ROWID) ENAME
------------------ ------------------ ----------
AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITH
AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN
AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD
AAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONES

43.CONVERT(c,dset,sset)
將源字串 sset從一個語言字元集轉換到另一個目的dset字元集
SQL> select convert(strutz,we8hp,f7dec) "conversion" from dual;
conver
------
strutz