Active Record 查询 select 个条目，该条目还没有我已经投过的票

Question

我有以下三个模型

判断（设计用户）

Judge.column_names
=> ["id", "email", "encrypted_password", "reset_password_token", "reset_password_sent_at", "remember_created_at", "sign_in_count", "current_sign_in_at", "last_sign_in_at", "current_sign_in_ip", "last_sign_in_ip", "created_at", "updated_at", "confirmation_token", "confirmed_at", "confirmation_sent_at", "unconfirmed_email"]

class Judge < ActiveRecord::Base
   has_many :votes
end

条目

Entry.column_names
 => ["id", "entrant_id", "title_of_work", "price", "created_at", "updated_at", "media_file_name", "media_content_type", "media_file_size", "media_updated_at", "paid", "height", "width", "type_of_media"]

class Entry < ActiveRecord::Base
    belongs_to :entrant
    has_many :votes
end

投票

Vote.column_names
=> ["id", "entry_id", "judge_id", "score", "created_at", "updated_at"]

class Vote < ActiveRecord::Base
    belongs_to :entry
    belongs_to :judge
end

我需要执行以下操作的查询

如果我以法官的身份登录，select 一个人支付了入场费，那还没有我已经投过的票。

我有这个，但它似乎不起作用

Entry.where(:paid => 1).includes(:votes).where.not(votes: { id: nil }).where.not(votes: {judge_id: current_judge.id }).first

我正在尝试创建一个显示可以投票的 'entry' 的页面。投票后，投票 table 中将有一条记录，并且永远不会再次显示。有很多法官，所以这些规则中的每一个都适用于每个法官。

有更好的方法吗？

Answer 1

如果你的意思是说你是法官，想要获取已付费但没有任何投票的参赛作品？那么以下查询可能会对您有所帮助：Entry.includes(:vote).where('paid = 1 and votes.judge_id <> ?', current_judge.id).references(:votes)

Answer 2

这可能会解决您的问题

Entry.includes(:votes).where(paid: 1).where("votes.judge_id != ? ", current_judge.id)

Active Record 查询 select 个条目，该条目还没有我已经投过的票

Active Record Query to select an entry, that does not already have a vote that I have already given

activerecord

ruby-on-rails

ruby-on-rails-4.2

ruby-2.2