Question

"Error: nothing to repeat  
   .link/test.getTest@file:www/js/directives.js:336:28  
   .link/<@file:www/js/directives.js:357:76"

我需要列出所有产品及其order_item的总和及其total_price的总和

class Product < ActiveRecord::Base

      belongs_to  :category
      has_many  :order_items, dependent: :destroy
    end


class OrderItem < ActiveRecord::Base
  belongs_to :order
  belongs_to :product
end

Answer 1

尝试此查询

select a.name,sum(quantity) as quantity ,sum(total_price) as total_price from 
Product a
join OrderItem b on a.id=b.product_id
Group by a.name

Answer 2

select p.name, sum(o.quantity) as quantity, sum(o.total_price) as total_price
from Product p
  join OrderItem o on p.id = o.product_id
group by p.name

Answer 3

尝试使用此活动记录查询。只需验证您可以使用的列，表名和关联，如：

   OrderItem.joins(:product).select("products.name as name,sum(total_price) as total_price , sum(quantity) as total_quantity").group("order_items.product_id").as_json

Answer 4

p = Product.first
p.order_items.sum(:quantity)

我希望这也有帮助

has_many和sum活动记录

4 个答案: