Ruby on rails 轨道3。如何进行嵌套属性查询？

我有一份发货发票；发票属于装运货物。装运表是包含客户id的表

我需要找到所有发票

• 针对特定客户和
• 客户帐户余额为0的

我尝试过许多不同的方法，但似乎都不管用，最后一种方法让我出错

private method select

或类似的东西

reports_controller.rb
i = Invoice.where("customer_open_balance != 0")
s = Shipment.find_by_customer_id(@customer.id)
shipment_ids_from_invoices = i.map{|x| x.shipment_id}
@shipments = s.select{|z| shipment_ids_from_invoices.include? z.id}

这行吗

@shipments = Shipment.joins(:invoice).where(:customer_id => @customer.id).where("customer_account_balance <> 0")

---

您是否将

has_one:invoice

放在了shipping.rb中，并且

belts_to:shipping

放在了invoice.rb中？

这给了我一些错误，但我喜欢创建范围的方法。我想我会把答案结合起来。谢谢！：）

class Invoice

  belongs_to :shipment

  scope :with_customer, lambda { |customer_id| joins(:shipment).where(:customer_id => customer_id) }

  scope :cero_balance, joins(:shipment).joins(:customer).where("customer_account_balance <> 0")

end

class Invoice

  belongs_to :shipment

  scope :with_customer, lambda { |customer_id| joins(:shipment).where(:customer_id => customer_id) }

  scope :cero_balance, joins(:shipment).joins(:customer).where("customer_account_balance <> 0")

end

#for a particular customer with id 1
Invoice.with_customer 1

#that have customer_account_balance of 0
Invoice.cero_balance