如何根据Rails中的单列计算记录与其他记录相比的排名? [英] How to calculate a record's ranking compared to others based on a single column in Rails?

问题描述

假设我有 User 模型，其中有一列名为 point.

Assuming I have User model with a column called point.

与所有其他 User 行相比，我如何获得实例的排名.

How can I get an instance's ranking compared to all other User rows.

推荐答案

用户的排名可以被认为是其他用户的分数比他们多，再加上 1.正如 Mischa 在评论中指出的，一个合适的地方这将在用户模型本身中，如:

The user's rank can be thought of as the number other users with more points than them, plus 1. As Mischa pointed out in the comments, an appropriate place for this would be in the User model itself, as in:

def ranking
   User.where('point > ?', point).count + 1
end

然后您可以将其称为:

Rank: <%= @user.ranking %>

这有一个缺点，即在同一排名中对具有相同点数的用户进行排名.您必须为这种情况决定决胜局".

This has the downside of ranking users with the same number of points at the same rank. You'll have to decide on a "tiebreaker" for that case.

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