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
https://www.nowcoder.com/practice/6a62b6c0a7324350a6d9959fa7c21db3
select c.dept_no,c.dept_name,count(a.emp_no) as sum from (salaries as a left join dept_emp as b on a.emp_no=b.emp_no left join departments as c on b.dept_no=c.dept_no) group by c.dept_no order by c.dept_no
主要是会卡在这个sum是用count函数来计算,另外不需要去重