ActiveRecord 根据列表中具有值的关联记录进行条件查找
使用以下 Rails 模型：
class Group < ActiveRecord::Base
has_many :group_locations, :dependent => :restrict
has_many :locations, :through => :group_locations, :dependent => :restrict
end
class Location < ActiveRecord::Base
has_many :group_locations, :dependent => :destroy
has_many :groups, :through => :group_locations
end
class GroupLocation < ActiveRecord::Base
belongs_to :group
belongs_to :location
end
我试图查找与字符串“group_list”中包含的多个组中的至少一个相关联的所有位置（例如“1 ,2,3,4,5")。如果它是位置记录中的字段，我将指定“*field in (#{group_list})*”条件。但是，当我想要至少拥有一个其“group_id”在列表中的位置的“group_location”（或者，一个其 group_id 在列表中的“组”）时，我该如何实现我的目标。
我知道如何用纯 SQL 做到这一点，但是如何用 Rails 做到这一点？
With the following Rails models:
class Group < ActiveRecord::Base
has_many :group_locations, :dependent => :restrict
has_many :locations, :through => :group_locations, :dependent => :restrict
end
class Location < ActiveRecord::Base
has_many :group_locations, :dependent => :destroy
has_many :groups, :through => :group_locations
end
class GroupLocation < ActiveRecord::Base
belongs_to :group
belongs_to :location
end
I am trying to Find all of the locations that are associated with at least one of several groups contained in the string "group_list" (e.g. "1,2,3,4,5"). If it was a field from the Location record, I would specify a condition of "*field in (#{group_list})*". But how do I accomplish my goal when I want to have at least one of the location's "group_location" whose "group_id" is in the list (or, alternatively, one "group" whose group_id is in the list).
I know how to do it with pure SQL, but how do you do it with Rails?
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@太郎你是对的。首先添加代码
然后我继续定义一个范围只是为了使其成为一个漂亮的包：
感谢您的帮助。
@taro You are right. Started by adding the code
Then I proceeded to define a scope just to make it a nice package:
Thanks for your help.