MOD10 Validation for Credit Card and Checks

Question

Hi Friends, I am looking for MOD10 Validation function for Credit Card and Checks.

Answer 1

See example below. Suggest you check this a.) suits your requirements and b.) actually works ;-)
FUNCTION luhn_check_digit (
   n IN VARCHAR2)
   RETURN NUMBER
IS
   SUBTYPE st_num IS NUMBER (10);
   m st_num := 0;
   FUNCTION luhn_sum (
      n IN VARCHAR2)
      RETURN NUMBER
   IS
      l st_num := LENGTH (n);
      t st_num := 0;
      s st_num := 0;
   BEGIN
      <<multiply>>
      FOR i IN 0 .. (l - 1) LOOP
         t := SUBSTR (n, (l - i), 1) * (MOD ((i + 1), 2) + 1);
         <<combine>>
         FOR j IN 1 .. LENGTH (t) LOOP
            s := s + SUBSTR (t, j, 1);
         END LOOP combine;
      END LOOP multiply;
      RETURN s;
   END luhn_sum;
BEGIN
   m := luhn_sum (n);
   RETURN (CEIL (m / 10) * 10) - m;
END luhn_check_digit;