passing a list to a function and returning a recordset

I have the following function.  The function is called by:
   fn_grd_students('(1,2,3,4)','(5,6,7,8)');

I want to pass two lists, do a select based on these lists and return a
recordset to the caller.

And it doesn't work...

Any help would be appreciated.

Thanks.


create or replace function fn_grd_students(text,text)   returns refcursor as

'
declare   -- in params   student_list_in alias for $1;   assign_list_in alias for $2;
   -- local var   rc refcursor;
begin
   execute ''open rc for select b.user_id,               b.grd_assignment_id,               a.last_name,
b.grd_grade_id,              c.grade_desc,               c.grade_value        from               user_common a,
     grd_student_grades b,               grd_grades c        where               b.user_id = a.user_id
andb.grd_assignment_id in '' || assign_list_in ||               '' and b.grd_grade_id = c.grd_grade_id and '' ||
      '' a.user_id in '' || student_list_in
 

;

return rc;
end;
'
language 'plpgsql'
;