How do i return the count of matching characters in 2 string

Question

hi guys,
is there any comparision function in oracle that return the number of matching character between 2 string ?
example - 'josephine' and 'johnny'
return 3 ('j','o' and 'n')
please advice,
Best Regards,
Noob

Answer 1

Hi,
Type creation:
CREATE TYPE t_character AS OBJECT
   v_character varchar2(1)
CREATE TYPE characterList AS TABLE OF t_character;
/Function creation:
CREATE OR REPLACE FUNCTION fnc_compare_string(p_string_1 IN VARCHAR2,
                                              p_string_2 IN VARCHAR2) RETURN VARCHAR2 IS
   RESULT  VARCHAR2(4000);
   v_list1 characterList := characterList();
   v_list2 characterList := characterList();
   v_first BOOLEAN := TRUE;
   c_separator CONSTANT VARCHAR2(1) := ',';
BEGIN
   FOR i IN 1 .. length(p_string_1) LOOP
      v_list1.EXTEND;
      v_list1(i) := t_character(substr(p_string_1,
                                       i,
                                       1));
   END LOOP;
   FOR i IN 1 .. length(p_string_2) LOOP
      v_list2.EXTEND;
      v_list2(i) := t_character(substr(p_string_2,
                                       i,
                                       1));
   END LOOP;
   FOR reg IN (SELECT DISTINCT *
                 FROM TABLE(CAST(v_list1 AS characterList))
               INTERSECT
               SELECT DISTINCT * FROM TABLE(CAST(v_list2 AS characterList))) LOOP
      IF v_first THEN
         v_first := FALSE;
         RESULT  := RESULT || reg.v_character;
      ELSE
         RESULT := RESULT || c_separator || reg.v_character;
      END IF;
   END LOOP;
   RETURN(RESULT);
END fnc_compare_string;Test:
Connected to Oracle Database 10g Express Edition Release 10.2.0.1.0
Connected as hr
SQL> select fnc_compare_string('post', 'most') from dual;
FNC_COMPARE_STRING('POST','MOS
o,s,t
SQL> select fnc_compare_string('post', 'jhon') from dual;
FNC_COMPARE_STRING('POST','JHO
o
SQL> select fnc_compare_string('post', 'was') from dual;
FNC_COMPARE_STRING('POST','WAS
s
SQL> select fnc_compare_string('post', 'w') from dual;
FNC_COMPARE_STRING('POST','W')
SQL> Regards,