select 
t1.emp_no,de.emp_no,t1.emp_salary,salaries.salary as manager_salary
from dept_manager as de
inner join salaries
on de.emp_no = salaries.emp_no
inner join 
(select dept_emp.emp_no,dept_emp.dept_no,salaries.salary as emp_salary
from dept_emp inner join salaries 
on dept_emp.emp_no = salaries.emp_no
where dept_emp.emp_no not in (select emp_no from dept_manager))t1
on de.dept_no = t1.dept_no
where t1.emp_salary > salaries.salary

1.查找出所有经理及其薪资
2.查找出所有非经理的员工的薪资
3.通过部门关联表将上两个结果连起来
4.判断经理和员工薪资的大小