select a.emp_no,a.salary,b.t_rank 
from 
    salaries a join 
    (
        select salary,dense_rank() over(order by salary desc) t_rank 
        from 
            salaries 
            group by salary
            ) b 
            on a.salary=b.salary 
            order by a.salary desc;


#找一个表，由薪水跟t_rank组成
#RANK()函数