Question

Let’s say

• User has many projects (projects created by user)
• User has many memberships

Also

• User has many joined_projects through memberships (projects created by other users)

What is the best way to join ‘projects’ and ‘joined_projects’ to get all the projects user has access to hopefully without using sql.

Other option would be creating membership for all projects even if user owns the project, but that generates duplicate data on the database.

Answer 1

The join method in ActiveRelation always uses inner joins, so there’s no way to do this “properly” from an SQL perspective. However, you can always set up a counter_cache and query it like so:

class User < ActiveRecord::Base
  has_many :projects, :counter_cache => true
  has_many :joined_projects, :through => :memberships, :counter_cache => true

  class << self
    def has_projects
      where('projects_count > 0 OR joined_projects_count > 0')
    end
  end

  def all_projects
    projects + joined_projects
  end
end

It might hit a normalization nerve but should get the job done.