I am implementing a betting system and each user has a balance , how can i find a rank of a user using activerecord methods? thanks for your help.
a. 获得用户排名,
Users.all(:order => "balance").index(a_particular_user)
这应当给您一个特定用户的指数(等级)。
如果用户众多,解决办法就会稍有提高:
Users.order(:balance).pluck(:id).index(a_particular_user_id)`
这样,你们的 app子就不要拉开和瞬间整条
几天前,我仅问同一问题。
我的解决办法与@Drew Johnson所建议的办法相同(User.all.index current_user)。 但是,我需要“频率解决方案”和“Vlad Zloteanu”给我一个伟大的想法:
User.count(:order => "balance", :conditions => [ balance < (?) , current_user.balance])
这是大数据表的快速解决方案。
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