注意与上一题的区别
查找所有员工的last_name和first_name以及对应部门编号dept_no
http://www.nowcoder.com/questionTerminal/dbfafafb2ee2482aa390645abd4463bf
employees表里面的所有都显示,
employees在左边
所以 left join
select e.last_name,e.first_name,d.dept_no from employees as e left join dept_emp as d on e.emp_no=d.emp_no