Rails/ActiveRecord:如何根据与相关模型的大多数关联来排序记录?

class Tourist < ApplicationRecord
  has_many :visits
  has_many :countries, through: :visits
end

class Country < ApplicationRecord
  has_many :visits
  has_many :tourists, through: :visits
end

class Visit < ApplicationRecord
  belongs_to :country
  belongs_to :tourist
end

我正在设法按旅游协会的数目把这些国家分类。

Country.joins(:tourist).group(:tourist_id).order('COUNT(*)')

然而,这似乎并不完全正确。首先,我得到一个折旧警告。

DEPRECATION WARNING: Dangerous query method (method whose arguments are used as raw SQL) called with a non-attribute argument(s): "COUNT(*)". Non-attribute arguments will be disallowed in Rails 6.0. This method should not be called with user-provided values, such as request parameters or model attributes. Known-safe values can be passed by wrapping them in Arel.sql(). (called from __pry__ at (pry):61)

而且,我不认为我得到了正确的值,因为 first 是零。

什么是获得关联最多的记录的正确方法?