Rails 3 activerecord: sort by association count - rails 3 activerecord: order by count on Association

problem ：

I have a model named Song . I have a name called Song Model of .I also have a model named Listen . I have another one called Listen Model of .A Listenbelongs_to :song , and a song :has_many listens (can be listen to many times).A Listenbelongs_to :song And songs :has_many listens （ You can listen to it many times ）.

In my model I want to define a method self.top which should return the top 5 songs listened to the most. In my model , I want to define a method self.top , It should return to the top of the list 5 A song .How can I achieve that using the has_many relation? How to use has_many Relationships achieve this ？

I'm using Rails 3.1. I am using Rails 3.1.

Thanks! thank you ！

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Solution ：

Reference resources ： https://stackoom.com/en/question/aUE9