题解 | #获取当前薪水第二多的员工的emp_no以及其对应的薪水salary#

法一: 窗口函数（由于可能有相同工资的多个人，所以不用rank（），而用dense_rank()）

select emp_no, salary
from (
    select emp_no, salary,
    dense_rank() over(order by salary desc) as posn
    from salaries
)rk
where rk.posn = 2
order by emp_no

法二：order by + limit(由于可能有相同工资的多个人,须在salary前面加distinct)

select emp_no, salary
from salaries
where salary = (
    select distinct salary
    from salaries
    order by salary desc
    limit 1,1
)
order by emp_no