题解 | #查找所有员工的last_name和first_name以及对应的dept_name#

select
    t.last_name,t.first_name,d.dept_name 
from
    (select 
        e.last_name,e.first_name,de.dept_no
    from 
        employees as e
    left join 
    dept_emp as de
    on 
        de.emp_no = e.emp_no) as t
left join 
    departments as d
on 
    d.dept_no = t.dept_no;