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
1.salaries左连接dept_emp，建立新表deptNo_sum记录dept_no和sum
2.departments内连接deptNo_sum
from departments depts join #[departments内连接deptNo_sum] (select de.dept_no,count(*) as sum from salaries s left join dept_emp de on s.emp_no = de.emp_no group by de.dept_no) deptNo_sum #[salaries左连接dept_emp，新表deptNo_sum记录了dept_no和sum] on depts.dept_no=deptNo_sum.dept_no order by depts.dept_no;
这样才显得专业