oracle字符串函数

1 字符串连接

 

SQL> select 'abc' || 'def' from dual;

'ABC'|
------
abcdef

2　小写
SQL>select lower('ABC012');
lower
--------
abc012

3　大写

select upper('abc012');

upper
--------
ABC012

4　 左补全

 

select lpad('abc', 5, '0');

lpad
-------
00abc

select lpad('abc', 5, '012');

lpad
-------
01abc

 

第3个参数为空时，缺省为space

 

select lpad('abc', 5);

lpad
-------
   abc

select lpad('abc', 5, ' ');

lpad
-------
   abc

 

5 　右补全

 

select rpad('abc', 5, '0');

rpad
-------
abc00

select rpad('abc', 5, '012');

rpad
-------
abc01

 

6　左空白删除

select ltrim('          abc');

ltrim
-------
abc
7　右空白删除

 

select ltrim('abc          ');

     ltrim
---------------
abc

 

 8　左右空白删除

select trim('          abc          ');

btrim
-------
abc

9　字符串替换

 

SQL> SELECT TRANSLATE('ababab' , 'a' , '1') FROM DUAL;

TRANSL
------
1b1b1b

 

10　取子字符串

 

SQL> select substr('abc012', 3, 2) from dual;

SU
--
c0

 

11　字符串长度

 

SQL> select length('abc012') from dual;

LENGTH('ABC012')
----------------
               6

12　 数字转化成字符串

 

SQL> select to_char(123456, '999,999,999,999') from dual;

TO_CHAR(123456,'
----------------
         123,456

 

13　字符串转化为数字

 

SQL> select to_number('123' || '456', '999999999999') from dual;

TO_NUMBER('123'||'456','999999999999')
--------------------------------------
                                123456

SQL> select to_number('123,456', '999,999,999,999') from dual;

TO_NUMBER('123,456','999,999,999,999')
--------------------------------------
                                123456