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
select dp.dept_no,dp.dept_name,count(s.emp_no) as sum from salaries s
left join dept_emp de ON s.emp_no=de.emp_no
left join departments dp ON de.dept_no=dp.dept_no
group by dp.dept_no
order by dp.dept_no