ActiveRecord query: order by a sum on an included model

Question

• Project has_many :items
• Item belongs_to :project

I'm trying to get the projects sorted by the total price of their respective items. Something like:

Project.includes(:items).order('SUM(items.price)')

With this code, ActiveRecord returns only the first project. What am I missing?

Answer 1

I've not tried the v3 stuff out yet, but I'd assume it would be something like

Product.joins(:items).group('products.id').order('SUM(items.price)')