


How to Retrieve the Top 5 Most-Listened-To Songs Using Rails 3 ActiveRecord?
Retrieve Top Songs Based on Listen Count in Rails 3 ActiveRecord
You're seeking a method to retrieve the top 5 songs that have been listened to the most. ActiveRecord, in Rails 3.1, provides a powerful way to accomplish this task.
To begin, consider the Song model, which has a relationship with the Listen model. Each Listen relates to a specific Song, while each Song can have numerous Listens (indicating it has been listened to multiple times).
Within the Song model, you can define a self.top method to fetch the top 5 most-listened-to songs. This can be achieved by utilizing the has_many association:
class Song has_many :listens def self.top5 select("songs.id, OTHER_ATTRS_YOU_NEED, count(listens.id) AS listens_count") .joins(:listens) .group("songs.id") .order("listens_count DESC") .limit(5) end end
This code defines a named scope named top5 within the Song class. It leverages SQL to construct the desired query:
- select: Selects specific columns from the songs table, including an additional column named listens_count that counts the number of listens for each song.
- joins: Establishes a join between the songs and listens tables using the has_many association.
- group: Groups the results by songs.id to ensure the count is performed for each unique song.
- order: Orders the results in descending order based on the listens_count column.
- limit: Limits the results to the top 5 songs with the highest listen counts.
By invoking Song.top5, you can retrieve an array of the top 5 songs, with each song's attributes including the number of times it has been listened to. This allows for easy identification of the most popular songs within your application.
The above is the detailed content of How to Retrieve the Top 5 Most-Listened-To Songs Using Rails 3 ActiveRecord?. For more information, please follow other related articles on the PHP Chinese website!

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