-- select trim(leading '+' from '+2220E+1') AS t
/* select department_id, sum(salary) salary
from employees
group by department_id
order by salary desc
*/
with sum_salary as
( select department_id, sum(salary) salary
from employees
group by department_id )
select department_id
from sum_salary a
where a.salary = ( select max(salary) from sum_salary )