题解 | #汇总各个部门当前员工的title类型的分配数目#

select dp.dept_no, dept_name, title, count(*) as count
from dept_emp dp
join titles t
on dp.emp_no = t.emp_no
left join departments d
on dp.dept_no = d.dept_no
where dp.to_date = '9999-01-01'
group by dp.dept_no, title
order by dp.dept_no,title