DB development

The function will return the total salaries, but does not work correctly? CREATE function allsal( dep_name in varchar, job_title in varchar, count_name in varchar);

return number; as total_salaries number:=0;

begin

select SUM(salary) into total_salaries from employees where dname=dep_name OR job = job _title OR country = count_name;

return total_salaries; end;