Ruby-on-rails 两个表上的 Rails where 子句
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/12706834/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Rails where clause over two tables
提问by Martin
I have the following model in rails application
我在 rails 应用程序中有以下模型
category => company => store
Store has a belongs_tocompany and company has a belongs_tocategory relationship.
now i want to use a where method on a store object to retrieve all stores within the same category.
Store 有一个belongs_to公司，公司有一个belongs_to类别关系。现在我想在商店对象上使用 where 方法来检索同一类别中的所有商店。
I would like to have something like this
我想要这样的东西
@stores.nearbys(5).where("stores.company.category_id = xxx")
can somebody give me a tip on this
有人可以给我一个提示吗
回答by Erez Rabih
Try joins with where on the joined table:
尝试与连接表上的 where 连接：
@stores.nearbys(5).joins(:company).where("companies.category_id = xxx")
EDIT:
编辑：
To get the category of a store you will first have to delegate the category method to its company:
要获取商店的类别，您首先必须将类别方法委托给其公司：
class Store < ActiveRecord::Base
belongs_to :company
delegate :category, :to => :company
end
Now just call the method in your query:
现在只需在查询中调用该方法：
@stores.nearbys(5).joins(:company).where("companies.category_id = ?", self.company.id)
回答by Simone Carletti
wheresupports nested hash.
where支持嵌套哈希。
@stores.nearbys(5).where(:company => { :category_id => @category.id }, joins: company)
回答by Aayush Khandelwal
you can try this
你可以试试这个
@category = Category.find xxx
@store = @category.company.stores
