I want Rails to aggregate values by group (SUM) and display the aggregated results for each group.

default aggregate_result

  @record=current_user.records.includes(:practice).select("practice_item", "practice_time").group("practice_item").sum(:practice_time)
  logger.info "test#{@record}"
  gon.data=@record
  end

 started POST"/__better_errors/1d27c32fbb9084fd/variables" for::1 at 2020-06-2023:40:45+0900
Started GET "/records/3/aggregate_result" for::1 at 2020-06-20 23:40:46+0900
Processing by RecordsController # aggregate_result as HTML
  Parameters: {"id"=>"3"}
  User Load (0.1ms) SELECT "users".* FROM "users" WHERE "users". "id" = $1 ORDER BY "users". "id" ASCLIMIT $2 [["id", 3], ["LIMIT", 1]]
  ↳ /Users/user/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/activerecord-5.2.4.3/lib/active_record/log_subscriber.rb:98
   (0.6ms) SELECT SUM(practice_time) AS sum_practice_time, practice_item AS practice_item FROM "records" LEFT OUTER JOIN "PRacts" ON "PRacts"."record_id" = "records"."id "WHERE" records" . "user_id" [[PRODUCT_ID_IDERY]=1][PRODUCT_ID_ID_ID_IDERPY][PRICE] 11]
  ↳ app/controllers/records_controller.rb:57
test {"Multi-ball Practice"=>222, "Serve Practice"=>170, "Footwork"=>30, "All"=>22, "On-board Processing"=>120}
  Rendering records/aggregate_result.html.slim with in layouts/application
  Rendered records /_flash_messages.html.slim (2.0ms)
  Rendered records/aggregate_result.html.slim with in layouts/application (6.1ms)
  Rendered records /_header.html.slim (3.1ms)
  Rendered records /_footer.html.slim (1.6ms)
Completed 200 OK in 51ms (Views:29.4ms | ActiveRecord: 5.2ms)

class RecordsController<ApplicationController
before_action —Authenticate_user!

  def index
    @q=current_user.records.ransack(params[:q])
    @[email protected](distinct:true).includes(:practices).page(params[:page]).per(8)
  end

  def show
    @record=Record.find (params[:id])
  end

  def new
    @record=Record.new
    [email protected]
    [email protected]
    [email protected]
  end

  def create
    @record=Record.new(record_params)
    logger.info "######{@record.inspect}"
    [email protected]
      flash[:success] = "Your practice has been registered."
      redirect_to records_url
    else
      flash[:alert] = "Registration failed."
      render:new
    end
  end

  default
    @record=Record.find_by (id:params[:id])
  end

  default update
    @record=Record.find_by (id:params[:id])
    [email protected](record_params)
        flash[:success] = "Your practice has been updated."
        redirect_to records_url
      else
        flash [:alert] = "Update failed."
        render —edit
      end
  end

  def destroy
    record=Record.find_by (id:params[:id])
    record.destroy

    redirect_to root_path, notice: "Practice record deleted."
  end

  default_result
  @record=current_user.records.includes(:practice).select("practice_item", "practice_time").group("practice_item").sum(:practice_time)
  logger.info "test#{@record}"
  gon.data=@record
  end

  private

  default_user
    @user=current_user|User.new
  end

  record_params
    params.require(:record).permit(:record_id,:training_date,:learning_point, output_attributes:[:output_name,:id,:_destroy], practices_attributes:[:practice_item,:practice_time,:id,_attributes]:[:test_attributes],:[:practice_time,_attributes]:[:test_date,_attributes]:
  end
end

ActiveRecord::Schema.define(version:2020_05_25_064157)do

  create_table "practices", force: :cascade do | t |
    t.string "practice_item"
    t. integer "practice_time"
    t.bigint "record_id"
    t.datetime "created_at", null:false
    t.datetime "updated_at", null:false
    t.index["record_id", name: "index_practices_on_record_id"
  end

  create_table "records", force: :cascade do | t |
    t.string "user_id"
    t.text "learning_point"
    t.date "training_date"
    t.datetime "created_at", null:false
    t.datetime "updated_at", null:false
  end

 = render 'records/flash_messages'
h1 Report
canvas#myPieChart
script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.bundle.js"
javascript:
  varctx = document.getElementById("myPieChart");
  var myPieChart = new Chart (ctx, {
    type: 'pie',
    data: {
      labels: ["Serve Practice", "Footwork", "Third Ball Attack", "On-board Processing", "Multi-ball Practice", "All",
      datasets: [{
          backgroundColor: [
            'rgba(255,99,132,0.2)',
            'rgba (54, 162, 235, 0.2)',
            'rgba (255, 206, 86, 0.2)',
            'rgba (75, 192, 192, 0.2)',
            'rgba (75, 192, 192, 0.2)',
            'rgba(242, 68, 172, 0.2)'
          ],
          data —gon.data
      }]
    },
    options: {
      title: {
        display —true,
        text: 'Breakdown of practice content'
      }
    }
  });

= link_to 'Back to List', root_path, class: 'btn btn-primary'