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oracle+110個常用函數

   1、ASCII

  返回與指定的字符對應的十進制數;

  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,返回對應的字符;

  SQL> select chr(54740) zhao,chr(65) chr65 from dual;

  ZH C

  -- -

  趙 A

  3. CONCAT

  連接兩個字符串;

  SQL> select concat(010-,88888888)||轉23 XXX電話 from dual;

  XXX電話

  ----------------

  010-88888888轉23

  4. INITCAP

  返回字符串並將字符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)

  在一個字符串中搜索指定的字符,返回發現指定的字符的位置;

  C1 被搜索的字符串

  C2 希望搜索的字符串

  I 搜索的開始位置,默認為1

  J 出現的位置,默認為1

  SQL> select instr(oracle traning,ra,1,2) instring from dual;

  INSTRING

  ---------

  9

  6.LENGTH

  返回字符串的長度;

  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))

  ------ ------------ ---------------- ------------ --------- --------------------

  XXX 3 北京市海錠區 6 9999.99 7

  7.LOWER

  返回字符串,並將所有的字符小寫

  SQL> select lower(AaBbCcDd)AaBbCcDd from dual;

  AABBCCDD

  --------

  aabbccdd

  8.UPPER

  返回字符串,並將所有的字符大寫

  SQL> select upper(AaBbCcDd) upper from dual;

  UPPER

  --------

  AABBCCDD

  9.RPAD和LPAD(粘貼字符)

  RPAD 在列的右邊粘貼字符

  LPAD 在列的左邊粘貼字符

  SQL> select lpad(rpad(gao,10,*),17,*)from dual;

  LPAD(RPAD(GAO,1

  -----------------

  *******gao*******

  不夠字符則用*來填滿

  10.LTRIM和RTRIM

  LTRIM 刪除左邊出現的字符串

  RTRIM 刪除右邊出現的字符串

  SQL> select ltrim(rtrim( gao qian jing , ), ) from dual;

  LTRIM(RTRIM(

  -------------

  gao qian jing

  11.SUBSTR(string,start,count)

  取子字符串,從start開始,取count個

  SQL> select substr(13088888888,3,8) from dual;

  SUBSTR(

  --------

  08888888

  12.REPLACE(string,s1,s2)

  string 希望被替換的字符或變量

  s1 被替換的字符串

  s2 要替換的字符串

  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符串讀音相同的字符串

  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 剪掉前面的字符

  TRAILING 剪掉後面的字符

  如果不指定,默認為空格符

  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

  16.ACOS

  給出反余弦的值

  SQL> select acos(-1) from dual;

  ACOS(-1)

  ---------

  3.1415927

  17.ASIN

  給出反正弦的值

  SQL> select asin(0.5) from dual;

  ASIN(0.5)

  ---------

  .52359878

  18.ATAN

  返回一個數字的反正切值

  SQL> select atan(1) from dual;

  ATAN(1)

  ---------

  .78539816

  19.CEIL

  返回大於或等於給出數字的最小整數

  SQL> select ceil(3.1415927) from dual;

  CEIL(3.1415927)

  ---------------

  4

  20.COS

  返回一個給定數字的余弦

  SQL> select cos(-3.1415927) from dual;

  COS(-3.1415927)

  ---------------

  -1

  21.COSH

  返回一個數字反余弦值

  SQL> select cosh(20) from dual;

  COSH(20)

  ---------

  242582598

  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

  24.LN

  返回一個數字的對數值

  SQL> select ln(1),ln(2),ln(2.7182818) from dual;

  LN(1) LN(2) LN(2.7182818)

  --------- --------- -------------

  0 .69314718 .99999999

  25.LOG(n1,n2)

  返回一個以n1為底n2的對數

  SQL> select log(2,1),log(2,4) from dual;

  LOG(2,1) LOG(2,4)

  --------- ---------

  0 2

  26.MOD(n1,n2)

  返回一個n1除以n2的余數

  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捨入

  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

  30.SIN

  返回一個數字的正弦值

  SQL> select sin(1.57079) from dual;

  SIN(1.57079)

  ------------

  1

  • 31.SIGH

  返回雙曲正弦的值

  SQL> select sin(20),sinh(20) from dual;

  SIN(20) SINH(20)

  --------- ---------

  .91294525 242582598

  32.SQRT

  返回數字n的根

  SQL> select sqrt(64),sqrt(10) from dual;

  SQRT(64) SQRT(10)

  --------- ---------

  8 3.1622777

  33.TAN

  返回數字的正切值

  SQL> select tan(20),tan(10) from dual;

  TAN(20) TAN(10)

  --------- ---------

  2.2371609 .64836083

  34.TANH

  返回數字n的雙曲正切值

  SQL> select tanh(20),tan(20) from dual;

  TANH(20) TAN(20)

  --------- ---------

  1 2.2371609

  35.TRUNC

  按照指定的精度截取一個數

  SQL> select trunc(124.1666,-2) trunc1,trunc(124.16666,2) from dual;

  TRUNC1 TRUNC(124.16666,2)

  --------- ------------------

  100 124.16

  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)

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