题解 | 所有员工的last_name和first_name
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 e.last_name,e.first_name,d1.dept_name from employees e left join dept_emp d2 on e.emp_no=d2.emp_no left join departments d1 on d2.dept_no=d1.dept_no and d2.to_date='9999-01-01'
