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
方法二是自己写的,不知道怎么就过了。。,为什么方法二用in就不行,方法一是借鉴网友的:
方法一:
SELECT e1.first_name FROM
employees e1
WHERE
(SELECT count(*) FROM employees e2
WHERE e1.first_name <=e2.first_name)%2=1;
方法二:
select employees.first_name from employees,
(select first_name , (count(first_name)over(order by first_name ))as rank_ from employees e1
)as r
where r.rank_%2=1 and employees.first_name=r.first_name
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