[SQL]SecondHighestSalary_leatcode

https://leetcode.com/problems/second-highest-salary

Second Highest Salary - LeetCode

with base as(
select
    distinct salary
    , dense_rank() over (order by salary desc) rn
from employee
)
, base2 as (
select
    distinct salary
    , rn
    , max(rn) over () mx_rn
from base
)
select 
    if(mx_rn >= 2, salary, null) as SecondHighestSalary
    # salary as SecondHighestSalary
from base2
where if(mx_rn >= 2, rn = 2, rn = 1)