#自关联，薪水大于其的只有一条的就是第二名
select emp_no,salary,last_name,first_name
from (
select s.emp_no,s.salary,last_name,first_name,count(1) as rn
from salaries s 
inner join employees e on s.emp_no = e.emp_no 
inner join salaries s2 on s2.salary > s.salary 
group by s.emp_no,s.salary,last_name,first_name
)t
where rn =1