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 departments.dept_no,departments.dept_name,count(*) as sum from departments
inner join dept_emp on departments.dept_no=dept_emp.dept_no
inner join salaries on dept_emp.emp_no=salaries.emp_no
group by departments.dept_no order by departments.dept_no asc;
两次内连
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