oracle中的進制轉換

1.16進制轉換為10進制

可以通過to_number函數實作 

SQL> select to_number('19f','xxx') from dual;

TO_NUMBER('19F','XXX')

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

415

SQL> select to_number('f','xx') from dual;

TO_NUMBER('F','XX')

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

15

2.10進制轉換為16進制

可以通過to_char函數轉換

SQL> select to_char(123,'xxx') from dual;

TO_C

----

7b

SQL> select to_char(4567,'xxxx') from dual;

TO_CH

-----

11d7

3.2進制轉換為10進制

從Oracle9i開始,提供函數bin_to_num進行2進制到10進制的轉換

SQL> select bin_to_num(1,1,0,1) a,bin_to_num(1,0) b from dual;

A B

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

13 2

SQL> select bin_to_num(1,1,1,0,1) from dual;

BIN_TO_NUM(1,1,1,0,1)

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

29

3.進制轉換也可以通過自定義函數實作

以下函數來自AskTom網站,是Tom給出的例子,供參考:

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

l_num number default 0;

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;

return l_num;

end to_dec;

show errors

create or replace function to_hex( p_dec in number ) return varchar2

return to_base( p_dec, 16 );

end to_hex;

create or replace function to_bin( p_dec in number ) return varchar2

return to_base( p_dec, 2 );

end to_bin;

create or replace function to_oct( p_dec in number ) return varchar2

return to_base( p_dec, 8 );

end to_oct;

-The End-