left_join

This gem helps you doing LEFT JOINs between your ActiveRecord associations, so you can do this:

Book.left_join(:category)
# SELECT "books".* FROM "books"
# LEFT OUTER JOIN "categories"
# ON "books"."category_id" = "categories"."id"

It also supports chaining associations, e.g. Category.left_join(books: :authors).

Why?

See this blog post for details.

Add to your Gemfile:

gem 'left_join'

Or install it manually

gem install left_join

Fork the project.
Start a feature/bugfix branch.
Commit and push until you are happy with your contribution.
Make sure to add tests for it. This is important so I don't break it in a future version unintentionally.
Create a pull request.