create or replace procedure cnav_list_intersection
(
 p_result OUT long,
 p_list1 IN long,
 p_list2 IN long
)
IS
listValue varchar2(2000);
reststr long;
countit number;
BEGIN
 if (p_list1 is null or p_list2 is null) then
   p_result := null;
   return;
 end if;
 p_result:=null;
 countit :=0;
 listValue:=listfirst(p_list1,',');
 reststr:=listrest(p_list1,',');
 while (listValue is not null) loop
   listValue:=listfirst(reststr,',');
   reststr:=listrest(reststr,','); 
   if (listValue is not null) then
     if ( ListFind(listValue,p_list2,',') = 1) then
       countit := countit +1;  
       if (countit!=1) then
        p_result := p_result || ',';
       end if; 
       p_result := p_result || listValue;
     end if; 
   end if;        
 end loop;
END cnav_list_intersection;
/
show errors;