select des.emp_no,dms.emp_no as manager_no,des.salary as emp_salary,dms.salary as manager_salary
from (select de.emp_no,de.dept_no,sa.salary from dept_emp de join salaries sa on de.emp_no=sa.emp_no) as des  join 
(select dm.emp_no,dm.dept_no,sa.salary from dept_manager dm join salaries sa on dm.emp_no=sa.emp_no) as dms on 
des.dept_no=dms.dept_no where des.salary>dms.salary

分别将员工和管理者的表加入salaries表 产生的 des,dms表 然后where过滤处理 薪水