Rails Active Record Associations: fetch data from multiple table - ruby-on-rails

Question

I have tables in db as following migration script:
class CreateAppointments < ActiveRecord::Migration
def change
create_table :physicians do |t|
t.string :name
t.timestamps null: false
end
create_table :patients do |t|
t.string :name
t.timestamps null: false
end
create_table :appointments do |t|
t.belongs_to :physician, index: true
t.belongs_to :patient, index: true
t.datetime :appointment_date
t.timestamps null: false
end
end
end
And the model class looks like:
class Physician < ActiveRecord::Base
has_many :appointments
has_many :patients, through: :appointments
end
class Appointment < ActiveRecord::Base
belongs_to :physician
belongs_to :patient
end
class Patient < ActiveRecord::Base
has_many :appointments
has_many :physicians, through: :appointments
end
I'm able to pick all patients data of specific physician using:
patients = Physician.find(123).patients
The problem is, I need appointment_date, which is stored in appointment table, along with patient details. Somehow I'm not able to figure out how to fetch it.

Answer 1

Relation looks completely right so querying should be quite easy or are you having some problems?
If you need appointment_date i would probably query Appointments of Physician instead:
Physician.find_by(id: 123).appointments.each do |x|
print "Date: #{x.appointment_date}\n"
print "Patient: #{x.patient.name}"
end

Answer 2

You can join Patient and Appointment models to get the required data easily:
Patient.joins(:appointments).where(. . . ).select('appointments.appointment_date')
You can put the required condition in the where clause and add more attributes from the patients and appointments tables in the select clause that you want to select.
See Active Record Query Interface for more information on this.
Update
I misunderstood your question initially. Th easiet way to get what you want is pointed by midN in his answer.