SQL实战22. 统计各个部门的工资记录数

题目

解答

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