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 a.dept_no,a.dept_name,c.sum
from departments a
left join
(select d.dept_no,count(s.emp_no) as sum
from dept_emp d
inner join salaries s
on d.emp_no=s.emp_no
group by d.dept_no) c
on a.dept_no=c.dept_no
order by a.dept_no;
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