Oracle HowTo:Oracle中如何进行进制转换(转载)

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Oracle HowTo:Oracle中如何进行进制转换(转载)

1.16进制转换为10进制
可以通过to_number函数实现

[td=500]SQL> select to_number('19f','xxx') from dual;TO_NUMBER('19F','XXX')
----------------------
415SQL> select to_number('f','xx') from dual;TO_NUMBER('F','XX')
-------------------
15

2.10进制转换为16进制
可以通过to_char函数转换

[td=500]SQL> select to_char(123,'xxx') from dual;TO_C
----
7bSQL> select to_char(4567,'xxxx') from dual;TO_CH
-----
11d7

3.2进制转换为10进制
从Oracle9i开始,提供函数bin_to_num进行2进制到10进制的转换

[td=500]SQL> select bin_to_num(1,1,0,1) a,bin_to_num(1,0) b from dual;A B
----- ----------
13 2SQL> select bin_to_num(1,1,1,0,1) from dual;BIN_TO_NUM(1,1,1,0,1)
---------------------
29

3.进制转换也可以通过自定义函数实现
以下函数来自AskTom网站,是Tom给出的例子,供参考:

[td=500]create or replace function to_base( p_dec in number, p_base in number )
return varchar2
is
l_str varchar2(255) default NULL;
l_num number default p_dec;
l_hex varchar2(16) default '0123456789ABCDEF';
begin
if ( trunc(p_dec) <> p_dec OR p_dec < 0 ) then raise PROGRAM_ERROR; end if; loop l_str := substr( l_hex, mod(l_num,p_base)+1, 1 ) || l_str; l_num := trunc( l_num/p_base ); exit when ( l_num = 0 ); end loop; return l_str; end to_base; / create or replace function to_dec ( p_str in varchar2, p_from_base in number default 16 ) return number is l_num number default 0; l_hex varchar2(16) default '0123456789ABCDEF'; begin for i in 1 .. length(p_str) loop l_num := l_num * p_from_base + instr(l_hex,upper(substr(p_str,i,1)))-1; end loop; return l_num; end to_dec; / show errorscreate or replace function to_hex( p_dec in number ) return varchar2 is begin return to_base( p_dec, 16 ); end to_hex; / create or replace function to_bin( p_dec in number ) return varchar2 is begin return to_base( p_dec, 2 ); end to_bin; / create or replace function to_oct( p_dec in number ) return varchar2 is begin return to_base( p_dec, 8 ); end to_oct; /

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