diff --git a/app/controllers/homework_commons_controller.rb b/app/controllers/homework_commons_controller.rb
index 5d1733983..eb3576f24 100644
--- a/app/controllers/homework_commons_controller.rb
+++ b/app/controllers/homework_commons_controller.rb
@@ -37,8 +37,6 @@ class HomeworkCommonsController < ApplicationController
       @category = @main_category.course_second_categories.find_by(id: params[:category])
       tip_exception("子目录id有误") if !@category.present?
       @homework_commons = @homework_commons.where(course_second_category_id: params[:category])
-    elsif @homework_type == 4
-      @homework_commons = @homework_commons
     end
     @all_count = @homework_commons.size
 
diff --git a/app/models/course.rb b/app/models/course.rb
index b7bea6ec0..baed1efe6 100644
--- a/app/models/course.rb
+++ b/app/models/course.rb
@@ -32,7 +32,12 @@ class Course < ApplicationRecord
   has_many :teacher_course_members, -> { teachers_and_admin }, class_name: 'CourseMember'
   has_many :teacher_users, through: :teacher_course_members, source: :user
   has_many :course_messages, dependent: :destroy
+
   has_many :homework_commons, dependent: :destroy
+  has_many :normal_homeworks, -> { normals }, class_name: 'HomeworkCommon'
+  has_many :group_homeworks, -> { groups }, class_name: 'HomeworkCommon'
+  has_many :practice_homeworks, -> { practices }, class_name: 'HomeworkCommon'
+
   has_many :homework_group_settings
   has_many :graduation_works, dependent: :destroy
 
diff --git a/app/models/homework_common.rb b/app/models/homework_common.rb
index f198a7143..e510ca666 100644
--- a/app/models/homework_common.rb
+++ b/app/models/homework_common.rb
@@ -48,6 +48,9 @@ class HomeworkCommon < ApplicationRecord
   scope :search_homework_type, lambda {|num| where(homework_type:num)}
   scope :unified_setting, -> {where("unified_setting = ? ", 1)}
 
+  scope :normals,  -> {where(homework_type: %i[normal])}
+  scope :groups,  -> {where(homework_type: %i[group])}
+  scope :practices,  -> {where(homework_type: %i[practice])}
 
   # 是否显示参考答案
   def view_answer identity, user_id
diff --git a/db/migrate/20190820021047_migrate_course_task_position.rb b/db/migrate/20190820021047_migrate_course_task_position.rb
new file mode 100644
index 000000000..cf1b633bd
--- /dev/null
+++ b/db/migrate/20190820021047_migrate_course_task_position.rb
@@ -0,0 +1,13 @@
+class MigrateCourseTaskPosition < ActiveRecord::Migration[5.2]
+  def change
+    add_column :homework_commons, :position, :integer, :default => 0
+
+    Course.find_each do |course|
+      puts course.id
+      course.practice_homeworks.order("IF(ISNULL(homework_commons.publish_time),0,1), homework_commons.publish_time DESC,
+                                                  homework_commons.created_at DESC").reverse.each_with_index do |homework, index|
+        homework.update_columns(position: index + 1)
+      end
+    end
+  end
+end