HOW TO GET THE VALUES FROM JOIN TABLES:

You have to create two tables .

For example i take customer and product tables.

Consider you need to know about the product which is is particular customer First of all you need to create the rails app...

rails new jointable -d mysql

The above code will create the rails app with the mysql database...

The you need to create the models and join tables ☺

For model creation:
 1. rails g model customer name:string mail:string
 2. rails g model Product name:string

For the Join table :
1. rails g model Join
   

in db file you can create the migration data:

class CreateJoins < ActiveRecord::Migration[5.1]
def change
create_table :joins do |t|
t.references :customer
t.references :product
t.timestamps
end
end
end

Then you have to create  the migration :

   For the migration :

         rake db:migrate

   If you face any Problem :

         just run this : rake db:drop db:create db:migrate

Then you have to create the assosiation for Join table :

It is HBTM(has and belongs to many)

class Customer < ApplicationRecord

has_many :joins

has_many :products , through: :joins

end

class Join < ApplicationRecord

belongs_to :customer

belongs_to :product

end

class Product < ApplicationRecord

has_many :joins

has_many :customers , through: :joins

end

These Assosiation You have to create ...

Then open the rails console see the result how it comes...

In the rails console:

Thankyou friends ...