select last_name,first_name,dept_no
from (
select emp_no, last_name,first_name
from employees
)a
join
(
select emp_no,dept_no
from dept_emp
)b
on a.emp_no=b.emp_no
from (
select emp_no, last_name,first_name
from employees
)a
join
(
select emp_no,dept_no
from dept_emp
)b
on a.emp_no=b.emp_no