select emp_no,manager_no,salary,manager_salary
from (
    select salary manager_salary,a.emp_no manager_no,dept_no from salaries a inner join dept_manager b using(emp_no) where b.to_date="9999-01-01"
)t1 left join (
    select dept_emp.*,salary from dept_emp inner join  salaries using(emp_no) 
    where dept_emp.to_date = "9999-01-01" and salaries.to_date="9999-01-01"
)t2 using(dept_no)
where manager_salary < salary