Arel::SelectManager how to access the result including the projections - ruby-on-rails

Question

I am attempting to access the results of a join where columns of both tables are specified as part of a projection.
I have 2 models (Rails 4.2.11; Arel 6.0.4; Ruby 2.5.3)
# Table name: users
#
# id :integer not null, primary key
# name :string(255)
# email :string(255)
# created_at :datetime not null
# updated_at :datetime not null
class User < ActiveRecord::Base
has_many :photos
end
# Table name: photos
#
# id :integer not null, primary key
# name :string(255)
# created_by_id :integer
# assigned_id :integer
# created_at :datetime not null
# updated_at :datetime not null
# user_id :integer
class Photo < ActiveRecord::Base
belongs_to :user
end
creators = User.arel_table.alias('creators')
updaters = User.arel_table.alias('updaters')
photos = Photo.arel_table
photos_with_credits = photos.
join(photos.join(creators, Arel::Nodes::OuterJoin).on(photos[:created_by_id].eq(creators[:id]))).
join(photos.join(updaters, Arel::Nodes::OuterJoin).on(photos[:assigned_id].eq(updaters[:id]))).
project(photos[:name], photos[:created_at], creators[:name].as('creator'), updaters[:name].as('editor'))
# generated SQL
SELECT photos.name, photos.created_at, creators.name AS creator, updaters.name AS editor
FROM photos
INNER JOIN (SELECT FROM photos LEFT OUTER JOIN users creators ON photos.created_by_id = creators.id)
INNER JOIN (SELECT FROM photos LEFT OUTER JOIN users updaters ON photos.updated_by_id = updaters.id)
How I'd like to process the result
photos_with_credits.map{|x| "#{photo.name} - copyright #{photo.created_at.year} #{photo.creator}, edited by #{photo.editor}"}.join('; ')
This may be a very dumb question, but ...
I have not been able to find a way to use the SelectManager result to produce a meaningful output since map was deprecated (& removed) from the SelectManager class.
I would appreciate your help.

Answer 1

Simplified the activerecord / arel query builder
amended code
photos_with_credits = Photo.select([photos[:name], photos[:created_at], creators[:name].as('creator'), updaters[:name].as('editor')]).
joins(photos.outer_join(creators).on(photos[:created_by_id].eq(creators[:id])).join_sources).
joins(photos.outer_join(updaters).on(photos[:assigned_id].eq(updaters[:id])).join_sources)
photos_with_credits.map do |photo|
puts "#{photo.name} - copyright #{photo.created_at.year} #{photo.creator}, edited by #{photo.editor}".light_blue
end
amended SQL (simpler)
SELECT photos.name, photos.created_at, creators.name AS creator, updaters.name AS editor
FROM photos
LEFT OUTER JOIN users creators ON photos.created_by_id = creators.id
LEFT OUTER JOIN users updaters ON photos.assigned_id = updaters.id

Answer 2

We should figure out a way to trigger SelectManage and get ActiveRelation result, then we can iterate it by using map, etc.
So I would like to suggest:
Photo.join(photos_with_credits.join_sources).map do |photo|
"#{photo.name} - copyright #{photo.created_at.year} #{photo.creator}, edited by #{photo.editor}"}.join('; ')
end