好久不打卡了
查找所有员工的last_name和first_name以及对应的dept_name
https://www.nowcoder.com/practice/5a7975fabe1146329cee4f670c27ad55
select employees.last_name,employees.first_name,h.dept_name from employees left join (select s.dept_no,s.dept_name,d.emp_no from departments s left join dept_emp d on s.dept_no = d.dept_no) h on employees.emp_no = h.emp_no
