How to get the latest record from each group in ActiveRecord?

Question

In my Ruby on Rails application I have a database structure like this:

Project.create(:group => \"1\", :date => \"2014-01-01\")
Project.create(:group =         


        

Answer 1

Something like this?

Project.select(:group).map(&:group).uniq.each do |grp|
  puts Project.where(group: grp).order("date DESC").last
end

This will go through all your groups and identify the unique ones. In your example it should return ["1", "2"]. Then it iterates over that array and selects the last Project with a group id of 1 and the last Project with a group id of 2.

** Update **

Just realized you said "latest" and not "last" which required adding an order to ensure latest works. Last still pulls just one.