上周浏览次数最多的使用印象派宝石的物品

我有邮政模型，它是impressionable using 印象派 https://github.com/charlotte-ruby/impressionist宝石 我想显示上个月访问量最高的 10 个帖子。

这是我想出的方法：

Post.all.sort_by{|post| post.view_count_last_month}.first 10

and view_count_last_month方法在Post model:

def view_count_last_week
    impressionist_count(:start_date => 1.week.ago)
end

但我认为这对性能不利，因为它加载所有帖子，然后按view_count_last_month method.

最好的方法是什么？

Thanks

通过查看印象派 https://github.com/charlotte-ruby/impressionist宝石代码为协会 https://github.com/charlotte-ruby/impressionist/blob/master/lib/impressionist/is_impressionable.rb#L15-L20 and in 印象派计数 https://github.com/charlotte-ruby/impressionist/blob/master/app/models/impressionist/impressionable.rb#L31-L49，您实际上可以像这样创建自己的范围：

  scope :order_by_starting_at, -> (start_date){ 
    impressions_table = Impression.quoted_table_name

    query = if start_date.present?
      "#{impressions_table}.created_at >= '#{start_date}' AND "
    else
      ''
    end

    query += "#{impressions_table}.created_at <= '#{Time.now}'"

    order(%Q{
            COALESCE((
              SELECT
                COUNT(#{impressions_table}.impressionable_id)
              FROM
                #{impressions_table}
              JOIN
                #{Post.quoted_table_name} AS popular_posts
              ON
                popular_posts.id = #{impressions_table}.impressionable_id
              AND
                #{impressions_table}.impressionable_id = '#{self.to_s}'
              WHERE
                #{query}
             ), 0) DESC
          })
    }

  scope :view_counts_for_first,-> (number){  
    order_by_starting_at.limit(number) 
    }

现在你可以：

Post.order_by_starting_at(1.week.ago).limit(10)
Post.order_by_starting_at.limit(10)

EDIT:

然而，事实证明，这样的效果更好——

Post.joins(:impressions).where("impressions.created_at<='#{Time.now}' and impressions.created_at >= '#{start_time}'").group("impressions.impressionable_id").order("count(impression‌​s.id) DESC")