select tt.emp_no emp_no,(tt.salary-bb.salary) growth
from
(select t.salary,t.emp_no
from salaries t
where to_date='9999-01-01' ) tt
inner join
(select b.salary,b.emp_no
from salaries b inner join employees em on b.emp_no=em.emp_no and b.from_date=em.hire_date) bb on tt.emp_no=bb.emp_no 
order by growth