如何查詢rails中的多個表？

Question

我有三種模式。它們如下所示

class User < ApplicationRecord 
    has_one :shop 
    has_one :address 
end 

class Shop < ApplicationRecord 
    belongs_to :user  
end 

class Address < ApplicationRecord 
    belongs_to :user  
end 

地址模型有state_id列。現在，我想所有的商店，其店的老闆address.state_id爲123456

Answer 1

Shop.joins(user: :address).where(addresses: { state_id: 123456 }) 

Answer 2

您可以通過User描述Shop和Address關係。就像這樣：

# models/shop.rb 
class Shop < ApplicationRecord 
    belongs_to :user 
    has_one :address, through: :user 
end 

然後你就可以發出簡單的呼叫：

Shop.includes(:address).where(addresses: { state_id: 123456 })