我不确定这里发生了什么。我有一个我正在尝试创建的适用于我的协会的范围:
class Subscription < ActiveRecord::Base
belongs_to :subscriber, :class_name => "User"
belongs_to :subscribable, :polymorphic => true
end
create_table :products do |t|
t.string :name
t.decimal :price
t.decimal :cost_per_unit
t.integer :user_id
end
create_table :subscriptions do |t|
t.string :name
t.decimal :price
t.decimal :cost_per_unit
t.integer :subscriber_id
t.integer :subscribable_id
t.string :subscribable_type
end
class Product < ActiveRecord::Base
has_many :subscriptions, :as => :subscribable, :dependent => :destroy
def self.lower_prices
Product.includes(:subscriptions).
where("products.price < subscriptions.price OR products.cost_per_unit < subscriptions.cost_per_unit" )
end
end
我正在尝试将产品的较低价格与订阅进行比较,但这给了我错误:
ActiveRecord::StatementInvalid in Pages#subscribed_products
PGError: ERROR: missing FROM-clause entry for table "subscriptions"
LINE 1: ... WHERE (user_id != 2) AND (products.price < subscripti...
^
: SELECT COUNT(*) FROM "products" WHERE (user_id != 2) AND (products.price < subscriptions.price OR products.cost_per_unit < subscriptions.cost_per_unit)
这里有什么问题?