Rails，ActiveRecord_Associations_CollectionProxy调用ActiveRecord方法的方式

Question

Board＆BoardThread模型

class Board < ActiveRecord::Base
    has_many :board_threads
end

class BoardThread < ActiveRecord::Base
    belongs_to :board
    has_many :likes, as: :likable

    def select_with_likes
        select("*, (SELECT COUNT(likes.id) FROM likes WHERE likable_id = board_threads.id AND likable_type = 'BoardThread') AS likes_cnt")
    end
end

我想使用ActiveRecord_Associations_CollectionProxy类中的“ select_with_likes”，如下所示。

b = Board.first
b.board_threads.select_with_likes.order()...

有什么好方法可以解决此问题？

Answer 1

您可以将逻辑移至scope

class BoardThread < ActiveRecord::Base
    belongs_to :board
    has_many :likes, as: :likable

    scope :with_likes, -> {
        select("*, (SELECT COUNT(likes.id) FROM likes WHERE likable_id = board_threads.id AND likable_type = 'BoardThread') AS likes_cnt")
    }
end

board_threads = Board.first.board_threads.with_likes.order(...)

Answer 2

对代码稍作更改就是将self关键字添加到您的方法中，如下所示：

def self.select_with_likes
  select("*, (SELECT COUNT(likes.id) FROM likes WHERE likable_id = board_threads.id AND likable_type = 'BoardThread') AS likes_cnt")
end