Question

我正在尝试对我的模型进行一些计算，但生成的sql无法正常工作。

我有这个型号：

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Order控制器中创建了一个函数来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

这可以按预期工作，但现在我想按年份对这个总金额进行分组，所以我想尝试做这样的事情

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...

我做错了什么？有没有更好的方法来做到这一点？非常感谢你提前！

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

您似乎已将订单表命名为错误。您不要将表和字段括在引号中。

所以喜欢这个= group('orders.order_date')

不喜欢这个= group('"order"."order_date"')

Rails与group by和sum相加

1 个答案: