CODEWITHSUNDEEP
ruby-on-railsactiverecord
Colton Seal
Colton Seal

Reputation: 379

How to access data from a scope with a join

I have two tables, People and Vehicles. I created a scope that shows which people do not have Vehicles.

scope :person_has_no_vehicle, -> { joins("LEFT OUTER JOIN vehicles ON vehicles.person_id = people.id").where('Vehicles.person_id IS NULL').limit(100)}

In my View I have

<% @person.person_has_no_vehicle.each do |test| %>

How would I access data from my vehicles table?

I.E.

<% if test.vehicles.person_id == NIL %> <-- That does not work, but you get the general idea.

Upvotes: 1

Views: 91

Answers (1)

MrYoshiji
MrYoshiji

Reputation: 54882

First, I suggest you some refactor:

# FROM
scope :person_has_no_vehicle, -> { joins("LEFT OUTER JOIN vehicles ON vehicles.person_id = people.id").where('Vehicles.person_id IS NULL').limit(100)}
# TO
scope :without_vehicle, -> { includes(:vehicles).where(vehicles: { id: nil }).limit(100) }

Then in your view you can use:

<% People.without_vehicle.each do |people| %>
  # These People instances do not have any vehicle record associated
  # so `people.vehicles` in this loop should return an empty ActiveRecord::Relation

I don't understand why you "would access data from the vehicles table", the scope you want is the exact opposite: People without any vehicle associated.

Anyway, if you really want to test if there is not Vehicle corresponding to the People record, try this:

<% People.without_vehicle.each do |people| %>
  <%= "THIS GUY OWNS AT LEAST 1 VEHICLE!!" if people.vehicles.present? %>

Upvotes: 1

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