1. ASCII

返回与指定的字符对应的十进制数;

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给出整数,返回对应的字符;

SQL> select chr(740) zhao,chr(65) chr65 from dual;

ZH C

-- -

赵A

3. CONCAT

连接两个字符串;

SQL> select concat(010-,88888888)||转23 高乾竞电话 from dual;

高乾竞电话

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

010-88888888转23

4. INITCAP

返回字符串并将字符串的第一个字母变为大写;

SQL> select initcap(smith) upp from dual;

UPP

-----

Smith

5.INSTR(C1,C2,I,J)在一个字符串中搜索指定的字符,返回发现指定的字符的位置;

C1被搜索的字符串

C2希望搜索的字符串

I 搜索的开始位置,默认为1 J 出现的位置,默认为1 SQL> select instr(oracle traning,ra,1,2) instring from dual;

INSTRING

---------

9

6.LENGTH

返回字符串的长度;

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))

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

高乾竞 3 北京市海锭区 6 9999.99 7

7.LOWER返回字符串,并将所有的字符小写

SQL> select lower(AaBbCcDd)AaBbCcDd from dual;

AABBCCDD

--------

aabbccdd

8.UPPER返回字符串,并将所有的字符大写

SQL> select upper(AaBbCcDd) upper from dual;

UPPER

--------

AABBCCDD

9.RPAD和LPAD(粘贴字符)

RPAD在列的右边粘贴字符

LPAD在列的左边粘贴字符

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

LPAD(RPAD(GAO,1

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

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

不够字符则用*来填满

10.LTRIM和RTRIM

LTRIM删除左边出现的字符串

RTRIM删除右边出现的字符串

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

LTRIM(RTRIM(

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

gao qian jing

　　 11.SUBSTR(string,start,count)取子字符串,从start开始,取count个SQL> select substr(13088888888,3,8) from dual;

SUBSTR(

--------

08888888

12.REPLACE(string,s1,s2)

string希望被替换的字符或变量

s1被替换的字符串

s2要替换的字符串

SQL> select replace(he love you,he,i) from dual;

REPLACE(H

----------

i love you

13.SOUNDEX

返回一个与给定的字符串读音相同的字符串

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剪掉后面的字符

如果不指定,默认为空格符

15.ABS

返回指定值的绝对值

SQL> select abs(100),abs(-100) from dual;

ABS(100) ABS(-100)

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

100 100

16.ACOS

给出反余弦的值

SQL> select acos(-1) from dual;

ACOS(-1)

---------

3.1415927

17.ASIN

给出反正弦的值

SQL> select asin(0.5) from dual;

ASIN(0.5)

---------

.52359878

18.ATAN

返回一个数字的反正切值

SQL> select atan(1) from dual;

ATAN(1)

---------

.78539816

19.CEIL

返回大于或等于给出数字的最小整数

SQL> select ceil(3.1415927) from dual;

CEIL(3.1415927)

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

4

20.COS

返回一个给定数字的余弦

SQL> select cos(-3.1415927) from dual;

COS(-3.1415927)

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

-1