Oracle进制转换函数

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')

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0000 1010 0001 0001