# 按要求进行group by和count SELECT t.dept_no,t.dept_name,count(1) as sum FROM ( # 先进行计算所得到的连表信息获取所有符合的薪资信息 SELECT d.dept_name, de.dept_no, s.emp_no, s.salary FROM departments d, dept_emp de, salaries s WHERE d.dept_no = de.dept_no AND de.emp_no = s.emp_no )t GROUP BY dept_no,dept_name ORDER BY dept_no