This view shows a list of authors along with the title of their newest post, but without the date that post was published. This is because it implements a Greatest Per Group query – thus, avoiding the N+1 query problem – using custom query methods, which are quite limited.

View the source code:

Read the blog post explaining this approach.

Author Newest Post
J.D. Salinger Franny and Zooey
Jane Austen Persuasion
Charles Dickens Barnaby Rudge

About this App

This Ruby on Rails app demonstrates the concepts encompassed in a series of blog posts about Greatest Per Group queries in Rails. You can view the source code on Github.