redis - REIDS 排名问题， 取前后5名

Question

用 zAdd 加入排名

zAdd ranks 1000 老王
zAdd ranks 1001 如花
zAdd ranks 1002 死鱼
....

想取 用户老王及老王的前后各5名， 有没有简便方法？

谢谢。

Answer 1

First, get Lao Wang’s current ranking: ZRANK ranks 老王, assuming Lao Wang’s ranking is Nth.

(The top 5 I am talking about here refer to those with a higher score than Lao Wang, and the bottom 5 are those with a smaller score than Lao Wang)
Then Lao Wang’s top 5 are: ZRANGE ranks N+1 N+6,
Lao Wang’s last 5 are: ZRANGE ranks N-6 N-1.

To put it all together, plus Lao Wang himself, it is: ZRANGE ranks N-6 N+6.

Note: You must remember to first determine whether N-6 and N-1 are less than 0.