create or replace procedure award_bonus(emp_id number, sales_amt number) as
  commission real;
  comm_missing exception;
begin
  select commission_pct
    into commission
    from employees_test
   where employee_id = emp_id;

  if commission is null then
    raise comm_missing;
  else
    update employees_test
       set salary = nvl(salary, 0) + sales_amt * commission
     where employee_id = emp_id;
  end if;
end;
/
