Ruby on rails 使用命名范围查找关联行的数量（RubyonRails+；Searchlogic问题）

假设我有：

class ForumTopic < ActiveRecord::Base
  has_many :forum_posts
  named_scope :number_of_posts, ??????
end

class ForumPost < ActiveRecord::Base
  belongs_to :forum_topic
end

---

任何帮助都将不胜感激

你想按帖子数量排序，对吗

我认为如果您使用

：counter\u cache

会更容易，因为如果您这样做，您可以像这样订购：

class ForumTopic < ActiveRecord::Base
  has_many :forum_posts
  named_scope :by_number_of_posts, :order => "forum_posts_count"
end

# controller
ForumTopic.by_number_of_posts.all

并在

论坛主题

表上创建一个

论坛帖子数

列

我相信就是这样

class ForumTopic < ActiveRecord::Base
  has_many :forum_posts
  named_scope :by_number_of_posts, :order => "forum_posts_count"
end

# controller
ForumTopic.by_number_of_posts.all

class ForumPost < ActiveRecord::Base
  belongs_to :forum_topic, :counter_cache => true
end