# 部门员工表 select a.dept_no as dept_no ,a.dept_name as dept_name ,b.title as title ,count(b.title) as count_n from (select de.dept_no,de.dept_name,dem.emp_no from departments de join dept_emp dem on de.dept_no = dem.dept_no)a join (select t.emp_no,t.title from titles t )b on a.emp_no = b.emp_no gr...