How to use logical operator

Question

Hi ,
I hava a problem while using logical operators.
I wrote a procedure to compare two strings.please check the following.
CREATE OR REPLACE PROCEDURE comp_str(sour_str IN varchar2,targ_str IN varchar2) AS
leng_sour_str number:=NVL(length(sour_str),0);
leng_targ_str number:=NVL(length(targ_str),0);
leng_str number:=NULL;
BEGIN
IF sour_str IS NULL THEN
dbms_output.put_line(leng_targ_str);
elsif targ_str IS NULL THEN
     dbms_output.put_line(leng_sour_str);
ELSE
     select utl_match.edit_distance(leng_sour_str,leng_targ_str) into leng_str from dual;
END IF;
dbms_output.put_line(leng_str);
IF (leng_str > 0) OR (leng_sour_str > 0) OR (leng_targ_str > 0) THEN
dbms_output.put_line('Strings are not same');
ELSE
dbms_output.put_line('Strings are same');
END IF;     
END comp_str;
IF (leng_str > 0) OR (leng_sour_str > 0) OR (leng_targ_str > 0) statement is not verifying the conditions properly.
Please suggest me that how to write multiple conditions with OR Operator or any alternative.
thanks in advance.

Answer 1

They are working exactly as you expect it. The problem in your code is probably the "utl_match.edit_distance"-procedure. Do you know the outcome of this procedure?
Why don't you try something like
declare
  l_string1   varchar2(255) := 'String1';
  l_string2   varchar2(255) := 'String 2';
begin
  if length(l_string1) > length(l_string2) then
    dbms_output.put_line('String 1 is longer than String 2');
  else
    dbms_output.put_line('String 1 is shorter than String 2');
  end if;
end;This way, you can change one string or the other and see, how it works. With utl_match.edit_distance you need to know what exactly they are computing to see what the logical comparison is doing.