Ruby on rails Rails 3相当于复杂SQL查询

鉴于以下模型：

class Recipe < ActiveRecord::Base
  has_many :recipe_ingredients
  has_many :ingredients, :through => :recipe_ingredients
end

class RecipeIngredient < ActiveRecord::Base
  belongs_to :recipe
  belongs_to :ingredient
end

class Ingredient < ActiveRecord::Base
end

---

我不知道如何使用Arel或ActiveRecord进行关系划分。如果可以接受进行两次查询，则相当于：

with_scope(includes(:recipes)) do
  cream_recipes = Ingredient.where(:name => "cream").first.recipes
  chocolate_recipes = Ingredient.where(:name => "chocolate").first.recipes
end
@recipes_with_chocolate_and_cream = cream_recipes & chocolate_recipes

---

或者您可以直接使用来传递SQL。

您可以使用连接来折射SQL吗？Subselect并不是真正以“rails”的方式存在的，除了通过执行两个查询和使用Ruby，我认为这种方法可以保持代码的可读性，并且任何其他开发人员都很容易理解和快速学习+1您赢得奖金。。。毫无疑问，这是最好的答案！

with_scope(includes(:recipes)) do
  cream_recipes = Ingredient.where(:name => "cream").first.recipes
  chocolate_recipes = Ingredient.where(:name => "chocolate").first.recipes
end
@recipes_with_chocolate_and_cream = cream_recipes & chocolate_recipes