Question

我有以下课程：

class Product < ActiveRecord::Base
  has_one :total_purchase
end

class TotalPurchase < ActiveRecord::Base
  belongs_to :product
end

我的表格包含以下栏目（为清晰起见，我省略了大部分内容）：

Product
id | title | end_date | price | discount

TotalPurchase
id | product_id | amount

许多产品都有相同的产品。标题，products.end_date和totalpurchases.amount，我想在某些日期之间识别所有产品。我目前正在使用以下sql查询来识别它们：

Product.find_by_sql("select products.title, products.end_date, total_purchases.amount from products left join total_purchases on products.id = total_purchases.product_id where products.end_date > '2012-08-26 23:00:00' and productss.end_date < '2012-09-02 22:59:59' group by products.end_date, products.title, total_purchases.amount having count(*) > 1")

如何将上述内容编写为rails查询而不是使用find_by_sql？

Answer 1

Product.select('products.end_date, products.title, total_purchases.amount').
  joins('left join total_purchases on products.id = total_purchases.product_id').
  where('products.end_date > :start_date 
    and products.end_date < :end_date',
    :start_date => '2012-08-26 23:00:00', 
    :end_date => '2012-09-02 22:59:59').
  group('products.end_date, products.title, total_purchases.amount').
  having('count(*) > 1')

Rails，在postgres数据库中找到重复的条目

1 个答案: