How Can I Efficiently Retrieve the Top 5 Most Listened-To Songs Using ActiveRecord in Ruby on Rails?

Efficiently Retrieving Top Listened-To Songs Using ActiveRecord

In Ruby on Rails, retrieving the most popular records based on associated model counts is a common task. In this case, we have a Song model and a Listen model where each Listen belongs to a Song, and each Song can have multiple Listens. To determine the top five most listened-to songs, we need to access the association information in an efficient manner.

Using Named Scopes

ActiveRecord's named scopes provide a powerful way to encapsulate complex queries. They enable us to create reusable query criteria that can be easily invoked. For the given scenario, we can define a named scope called :top5 within the Song model:

class Song
  has_many :listens
  scope :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)

# Retrieve the top 5 most listened-to songs
songs = Song.top5

Query Breakdown

• select specifies the fields to be included in the result.
• joins establishes the join condition between the Song and Listen models.
• group groups the results by Song ID to count the number of Listens for each song.
• order sorts the results in descending order based on the listen count.
• limit restricts the result to the top 5 songs.

By invoking the :top5 named scope, we can obtain a collection of the top five songs with the associated count of listens, providing a concise and efficient way to extract the required data.

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