题解 | #汇总各个部门当前员工的title类型的分配数目#

多表连接，多个维度排序，以及分组聚合的考察 select c.dept_no,t.dept_name,e.title, count(*)as count from departments as t right join dept_emp as c on t.dept_no=c.dept_no left join titles as e on c.emp_no=e.emp_no group by c.dept_no,e.title order by c.dept_no,e.title asc;