Activerecord join with has_many :through

ActiveRecord::StatementInvalid: 
Mysql::Error: Unknown column 'schedules.id' in 'on clause': 
SELECT `schedules`.* FROM `schedules`   INNER JOIN `shops` ON 
(`schedules`.`id` = `shops`.`shop_id`)  INNER JOIN `areas` ON 
(`areas`.`id` = `shops`.`area_id`)

The correct sql statement should include 'schedules'.'shop_id' = 'shops'.'id' instead of 'schedules'.'id' = 'shops'.'shop_id'. What can I change in my models to make this happen?

Here are the models for these three classes:

class Area < ActiveRecord::Base  
  has_many :shops  
  has_many :schedules, :through => :shop  
end  

class Schedule < ActiveRecord::Base  
  belongs_to :shop  
  has_many :areas, :through => :shop  
end  

class Shop < ActiveRecord::Base  
  belongs_to :area # foreign key - area_id  
  has_many :schedule  
end

The command that created that sql command: Schedule.find :all, :joins => [:shop, :areas]

In db/schema.rb I have:

create_table "areas", :force => true do |t| 
  t.string   "campus"
  t.datetime "created_at"
  t.datetime "updated_at"
end 

create_table "shops", :force => true do |t|
  t.integer  "area_id"
  t.datetime "created_at"
开发者_如何学JAVA  t.datetime "updated_at"
end

create_table "schedules", :force => true do |t|
  t.integer  "shop_id"
  t.datetime "created_at"
  t.datetime "updated_at"
end

I think your query should be specified using the :include option like so

Schedule.find :all, :include => [:shops, :areas]

The :join option is for specifying join logic such as "INNER JOIN ..."