select emp_no,diff growth
from(
select a3.emp_no, a4.salary-a3.salary diff
from 
(select a1.emp_no, a2.salary
from employees a1 left join salaries a2
on a1.hire_date = a2.from_date) a3
left join (
    select emp_no, salary
    from salaries
    where to_date = "9999-01-01"
) a4
on a3.emp_no = a4.emp_no
) a5
where diff is not null
order by growth