题解 | #对于employees表中，给出奇数行的first_name#
对于employees表中，给出奇数行的first_name
http://www.nowcoder.com/practice/e3cf1171f6cc426bac85fd4ffa786594
结果无需排序的意思是不允许排序...只能用原来的表来join了
select
e.first_name
from employees e
left join
(select first_name,
rank() over(order by first_name asc) as rn
from employees) tmp
on e.first_name = tmp.first_name
where rn%2=1; 
