题解 | #统计各个部门的工资记录数#
统计各个部门的工资记录数
http://www.nowcoder.com/practice/6a62b6c0a7324350a6d9959fa7c21db3
三表左链接:
select de.dept_no, dm.dept_name, count(s.emp_no) sum from
(salaries as s left join dept_emp as de
on s.emp_no=de.emp_no)
left join departments as dm
on de.dept_no=dm.dept_no
group by de.dept_no
order by de.dept_no