how can print data form multiple table in rails association?

Question

i have created project, stage, task and sub_task scaffold. project has one to many association with stage, stage has one to many association with task and task has one to many association with sub task. i want to render each task's all sub_task in project#show, currently i am able to render all sub_tasks to each task.

routes.rb

  resources :projects do
    resources :stages do
      resources :tasks do
        resources :sub_tasks
      end
    end
  end

projects_controller.rb

  def show
    @project = Project.includes(stages: :tasks).find(params[:id])
    @stages = @project.stages
    @sub_tasks = SubTask.all
  end

Answer 1

You can include the subtasks along with tasks as follows:

 def show
    @project = Project.includes({stages: {tasks: :sub_tasks}}).find(params[:id])
    @stages = @project.stages
    # Now when you iterate through stages, you can fetch tasks associated with each stage, and for each task, you can get subtasks. All of this happens without additional DB queries because of the "includes"
  end

This would fetch all stages related to a project, all tasks related to each stage, and then sub tasks related to each task!