oracle中没有16进制转2进制的函数，，为了工作方便，自己写了一个
create or replace function hex_to_bin(hex varchar2) return varchar2 is
v_hex varchar2(10000);
v_len number;
v_var varchar2(10000);
v_result varchar2(10000) := '';
begin
v_hex := upper(hex);
v_len := length(v_hex);
for i in 1 .. v_len loop
v_var := case substr(v_hex, i, 1) when '0' then '0000' when '1' then '0001' when '2' then '0010' when '3' then '0011'
when '4' then '0100' when '5' then '0101' when '6' then '0110' when '7' then '0111' when '8' then '1000' when '9' then '1001'
when 'a' then '1010' when 'b' then '1011' when 'c' then '1100' when 'd' then '1101' when 'e' then '1110' when 'f' then '1111' end;
v_result := v_result || v_var || ' ';
end loop;
return v_result;
end hex_to_bin;
例子：
sql> select hex_to_bin('0a11') from dual;
hex_to_bin('0a11')
--------------------------------------------------------------------------------
0000 1010 0001 0001
16进制转10进制 ，oracle里面有个to_number函数 可以实现
sql> select to_number('abc','xxx') from dual;
to_number('abc','xxx')
----------------------
2748
10进制转16进制，oracle里面有个to_char函数 可以实现
sql> select to_char('2748','xxx') from dual;
to_char('2748','xxx')
---------------------
abc
2进制转10进制，oracle里面有个bin_to_num函数可以实现
sql> select bin_to_num(1,1,1,1,0) from dual;
bin_to_num(1,1,1,1,0)
---------------------
30