Notes posted by equivalent

arel_table order by

More objected way how to achieve ORDOR BY .… DESC is like this :

class User < ActiveRecord::Base
  has_many :status_changes

  def latest_status_change
    status_changes
     .order(StatusChange.arel_table['created_at'].desc)
     .first
  end
end

class StatusChange < ActiverRecord::Base
  belongs_to :user
end

resulting in:

SELECT "status_changes".* FROM "status_changes" WHERE "status_changes"."user_id" = 1 ORDER BY "status_changes"."created_at" DESC

Benefits:

• you are strictly bound to Modelclass name => renaming table in model will not break the sql code (of if it will, it will explicitly break the syntax on Ruby level, not DB level)

• you still have the benefit of explicitly saying what table.column the order should be

• easier to re-factor parts to Query Objects