与小组和包括的轨道总和

Question

我正在尝试通过模型进行一些计算，但是生成的SQL只是不起作用。

我有此模型：

class Order < ActiveRecord::Base
  attr_accessible :order_date
  has_many :order_products, dependent: :destroy
class OrderProduct < ActiveRecord::Base
  attr_accessible :amount
  belongs_to :tariff
  belongs_to :order_product_format
  belongs_to :product
class OrderProductFormat < ActiveRecord::Base
  attr_accessible :amount
class Tariff < ActiveRecord::Base
  attr_accessible :price

所以我在订单控制器中创建了一个函数，以获取所有订单的总量，如下所示

def self.global_total_amount
  OrderProduct.joins(:order_product_format, :tariff).sum '((order_products.amount * order_product_formats.amount ) * tariffs.price)'
end

这是按预期工作的，但是现在我想按一年的一个月进行分组，所以我想做类似的事情

def self.month_total_amount
  OrderProduct.includes(:order).joins(:order_product_format, :tariff, :order).group('"order"."order_date"').sum('((order_products.amount * order_product_formats.amount ) * tariffs.price)')
end

我会收到以下错误：

SELECT SUM(((order_products.amount * order_product_formats.amount ) * tariffs.price)) AS                     sum_order_products_amount_all_order_product_formats_amount_all_, "order"."order_date" AS order_order_date FROM "order_products" INNER JOIN "order_product_formats" ON "order_product_formats"."id" = "order_products"."order_product_format_id" INNER JOIN "tariffs" ON "tariffs"."id" = "order_products"."tariff_id" INNER JOIN "orders" ON "orders"."id" = "order_products"."order_id" GROUP BY "order"."order_date"
ActiveRecord::StatementInvalid: PG::Error: ERROR:  missing FROM-clause entry for table "order"
LINE 1: ...cts_amount_all_order_product_formats_amount_all_, "order"."o...

我在做什么错？有更好的方法吗？非常感谢您！

Answer 1

def self.month_total_amount
  OrderProduct.includes(:order).joins(:order_product_format, :tariff, :order).group('orders.order_date').sum('((order_products.amount * order_product_formats.amount ) * tariffs.price)')
end

您似乎将订单表命名为错误。您不将表和字段封闭在引号中。

所以像这样= group('orders.order_date')

不喜欢= group('"order"."order_date"')