SELECT a.dept_no,de.dept_name,a.title,a.count FROM (SELECT d.dept_no,t.title,COUNT(*) AS count FROM dept_emp d LEFT JOIN titles t ON d.emp_no = t.emp_no GROUP BY d.dept_no,title ORDER BY dept_no )a -- 连接统计 LEFT JOIN departments de ON a.dept_no = de.dept_no -- 连接把dept_name命名粘过来