use scope top hot

app/controllers/home_controller.rb

@@ -7,7 +7,7 @@ class HomeController < ApplicationController
     @job_count = Job.count
     @cities = City.all_cities
     @lasted_jobs = Job.order(created_at: :desc).limit(Job::NUMBER_LASTED_JOB)
-    @top_cities = City.top_hot.take(9)
-    @top_industries = Industry.top_hot.take(9)
+    @top_cities = City.top_cities(9)
+    @top_industries = Industry.top_industries(9)
   end
 end

app/models/city.rb

@@ -5,13 +5,9 @@ class City < ApplicationRecord
   has_many :city_jobs
   has_many :jobs, through: :city_jobs
   scope :all_cities, -> { select :id, :name }
-
-  def self.top_hot
-    hash = {}
-    data_cities = City.all
-    data_cities.each do |val|
-      hash[val.name] = val.jobs.count
-    end
-    hash.sort_by { |k, v| v }.reverse
+  scope :top_cities, ->(number) do joins(:jobs)
+    .group(:city_id)
+    .order(Arel.sql('count(jobs.id) DESC'))
+    .take(number)
   end
 end

app/models/industry.rb

@@ -4,14 +4,9 @@
 class Industry < ApplicationRecord
   has_many :industry_jobs
   has_many :jobs, through: :industry_jobs
-
-  def self.top_hot
-    hash = {}
-    data_industries = Industry.all
-    data_industries.each do |val|
-      hash[val.name] = val.jobs.count
-    end
-    hash = hash.select { |k, v| v.positive? }
-    hash.sort_by { |k, v| v }.reverse
+  scope :top_industries, ->(number) do joins(:jobs)
+    .group(:industry_id)
+    .order(Arel.sql('count(jobs.id) DESC'))
+    .take(number)
   end
 end

app/views/home/_box_nine_city.html.erb

@@ -4,14 +4,14 @@
       <span>Top thành phố</span>
     </div>
     <div class="row no-gutters">
-      <% @top_cities.each do |k,v| %>     
+      <% @top_cities.each do |city| %>     
         <div class="col-lg-4 col-md-4 col-sm-6 col-xs-12">
           <div class="box_info_city">
             <div class="ct_name">
-              <%= link_to k, '#' ,class: 'link_ct'%>    
+              <%= link_to city.name, '#' ,class: 'link_ct'%>    
             </div>
             <div class="ct_jobs_count">
-              <%= link_to  "#{v} công việc", '#' ,class: 'link_ct'%> 
+              <%= link_to  "#{city.jobs.count} công việc", '#' ,class: 'link_ct'%> 
             </div>  
           </div>
         </div>

app/views/home/_box_nine_industries.html.erb

@@ -4,14 +4,14 @@
       <span>Top các nghành phổ biến</span>
     </div>
     <div class="row no-gutters">
-      <% @top_industries.each do |name, jobs_count| %>     
+      <% @top_industries.each do |industry| %>     
         <div class="col-lg-4 col-md-4 col-sm-6 col-xs-12">
           <div class="box_info_city">
             <div class="ct_name">
-              <%= link_to name, '#',class: 'link_ct'%>    
+              <%= link_to industry.name, '#',class: 'link_ct'%>    
             </div>
             <div class="ct_jobs_count">
-              <%= link_to  "#{jobs_count} công việc", '#',class: 'link_ct'%> 
+              <%= link_to  "#{industry.jobs.count} công việc", '#',class: 'link_ct'%> 
             </div>  
           </div>
         </div>