扶手：使用顺序的has_many / belongs_to的关系 [英] Rails: order using a has_many/belongs_to relationship

问题描述

我想知道是否有可能使用find方法来订购的基础上与其他类的类的的has_many关系的结果。例如，

I was wondering if it was possible to use the find method to order the results based on a class's has_many relationship with another class. e.g.

# has the columns id, name
class Dog < ActiveRecord::Base
  has_many :dog_tags
end

# has the columns id, color, dog_id
class DogTags < ActiveRecord::Base
  belongs_to :dog
end

和我想这样做是这样的：

and I would like to do something like this:

@result = DogTag.find(:all, :order => dog.name)

感谢你。

推荐答案

您需要加入相关表的要求。

You need to join the related table to the request.

@result = DogTag.find(:all, :joins => :dog, :order => 'dogs.name')

注意狗是复数的：为了语句的

Note that dogs is plural in the :order statement.

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