思路：以部门关系表为主表关联部门经历表和s1,s2表，筛选即可
select
d1.emp_no
,d2.emp_no manager_no
,s1.salary emp_salary
,s2.salary manager_salary
from dept_emp d1
left join dept_manager d2 on d1.dept_no = d2.dept_no
left join salaries s1 on d1.emp_no = s1.emp_no
left join salaries s2 on d2.emp_no = s2.emp_no
where s1.salary > s2.salary