scope to class method

app/models/city.rb

@@ -2,9 +2,21 @@ class City < ApplicationRecord
    belongs_to :area
    has_many :jobs
    validates_presence_of :city_name
-   scope :top_city_by_job, ->{joins(:jobs).select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order.first(9)}
-   scope :top_city_by_job_nn, ->{joins(:jobs).where("cities.area_id = 2").select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order.first(9)}
-
-   scope :all_city_by_job, ->{joins(:jobs).select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order}
-   scope :all_city_by_job_nn, ->{joins(:jobs).where("cities.area_id = 2").select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order}
+   
+   def self.top_city_by_job
+     City.joins(:jobs).select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order.first(9)
+   end	
+   
+   def self.top_city_by_job_nn
+   	City.joins(:jobs).where("cities.area_id = 2").select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order.first(9)
+   end
+   
+   def self.all_city_by_job
+	 City.joins(:jobs).select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order
+   end
+   
+   def self.all_city_by_job_nn
+     City.joins(:jobs).where("cities.area_id = 2").select('cities.*, COUNT(jobs.id) as job_count').group('jobs.city_id').order(:job_count).reverse_order
+   end
+   
 end