题解 | 给出employees表中排名为奇数行的first_name

select 
    e.first_name as Georgi
from
    employees e
join 
    (
        select
        first_name,
        row_number() over(order by first_name asc) as rk
        from employees
    ) sub on e.first_name = sub.first_name
where
    mod(rk,2)!=0;