搜索字段类型哈希MongoID的多个键

Question

我想在字段类型哈希参考示例代码的多个键上应用过滤器

######工作代码

class Model
  include Mongoid::Document

  field :lD,    as: :load_date,       type:Time
  field :cls,   as: :classification,  type:Hash

  def self.base_filter(filters)
    Model.where("cls.#{filters}.r"=>true,"cls.#{filters}.t"=>"news",:load_date.gte=>1.month.ago).count
  end
end

######期望但不是工作代码

class Model
  include Mongoid::Document

  field :lD,    as: :load_date,       type:Time    
  field :cls,   as: :classification,  type:Hash

  def self.base_filter(filters)
    Model.where("cls.#{filters}"=>{'r'=>true,'t'=>"news"},:load_date.gte=>1.month.ago).count
  end
end

是否有类似的东西在MongoID中可用或者它在MongoDB中可用而不是我如何从MongoID调用它