题解 | #对所有员工的薪水按照salary降序进行1-N的排名#

我的方法：窗口函数

select emp_no,salary,dense_rank()over(order by salary desc) t_rank from salaries order by t_rank,emp_no

法二：不用group by，子查询可跟在select后面

select s2.emp_no,s2.salary,(select count(distinct s1.salary) from salaries s1 where s1.salary>=s2.salary)t_rank from salaries s2 
order by s2.salary desc,emp_no

法三：自连接+group by

select t1.emp_no, t1.salary, count( distinct t2.salary) as t_rank
from salaries t1,salaries t2 
where t1.salary <= t2.salary
group by t1.emp_no,t1.salary
order by t1.salary desc, t1.emp_no