SQL實戰22. 統計各個部門的工資記錄數

題目

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;