Question

我有一个rails应用程序，用户都有他们已经达到的分数。我想向用户显示其他用户的列表，这些用户的评分最接近他们自己。我希望这是用户得分+/-的顺序。我意识到我解释得很差，那么一个例子呢？

current_user.score = 825

user1.score = 827
user2.score = 818
user3.score = 824
user4.score = 887

所以当我这样做时：

User.where("score NEAR ?", current_user.score).order("proximity ASC") # I'm just making this up.

按此顺序返回结果：

用户3
用户1
用户2
USER4

我该怎么做？

Answer 1

User.where(:score => (current_user.score - offset)..(current_user.score + offset))

另一种方式：

# 5 higher scores higher than the user's 
User.where("score >= ? AND id != ?", current_user.score, current_user.id).order("score ASC").limit(5)
# 5 scores lower than the user's
User.where("score <= ? AND id != ?", current_user.score, current_user.id).order("score DESC").limit(5)

Answer 2

User.find(:all, :order => "ABS(score - #{current_user.score}) DESC")

或者，如果你想保留这些值：

User.find(:all,
          :select => "*, ABS(score - #{current_user.score}) as diff",
          :order => 'diff DESC')

当然你应该清理current_user.score。

基于Rails 3中整数的接近度进行查询

2 个答案: