Ruby on Rails paginate search products datas

paginate_search_datas.rb

per_page = 100
page = 0
total_page = (Product.count.to_f / per_page).ceil

total_page.times do
  products = Product.limit(per_page).offset(page * per_page)
  bill_items = bill_inventory_valuation_details products        # 符合条件的采购入库单数据，此方法的查找也必须对 products 进行批量查找
  sell_items = sell_inventory_valuation_details products        # 符合条件的销售出库数据
  package_items = package_inventory_valuation_details products  # 异常出库数据
  adjust = adjust_inventory_valuation_details products          # 调整仓库数据
  products.each do |product|
    datas = []
    datas += bill_items[product.id].map{|item| {id: item.id, quantity: item.quantity, price: item.price}}
    # 对查出的数据进行处理，构造最终结果
    ... ...
end

def bill_inventory_valuation_details products
    bill_items = PurchaseOrderBillItem.joins(:purchase_order_bill => :purchase_order).
                                       includes(:purchase_order_bill => :purchase_order).
                                       where("purchase_order_bills.status = ?", PurchaseOrderBill::STATUS[:finished]).
                                       where("purchase_order_bills.date BETWEEN ? AND ?", @start_date, @end_date).
                                       where("purchase_order_bill_items.product_id IN (?)", products.pluck(:id)).
                                       group_by(&:product_id)
  end

  def sell_inventory_valuation_details products
    sell_items = OutStorageOrderItem.joins(:out_storage_order).
                                     includes(:out_storage_order).
                                     where("out_storage_orders.out_storage_order_type = ?", 3).
                                     where("out_storage_orders.created_at BETWEEN ? AND ?", @start_date.beginning_of_day, @end_date.end_of_day).
                                     where("out_storage_orders.package_id IS NOT NULL OR out_storage_orders.package_group_id IS NOT NULL").
                                     where("out_storage_order_items.product_id IN (?)", products.pluck(:id)).
                                     group_by(&:product_id)
  end

  def adjust_inventory_valuation_details products
    adjust = AdjustInventoryRecord.where("the_date BETWEEN ? AND ?", @start_date, @end_date).where(product_id: products.pluck(:id)).group_by(&:product_id)
  end

  def package_inventory_valuation_details products
    package_items = PackageItem.eager_load(:package).where(product_id: products.pluck(:id)).
                                                  where("packages.state = ?", Package::STATE_VALUES[:processed]).
                                                  where("packages.dropship = ?", false).
                                                  where("packages.shipped_at >= ? AND packages.shipped_at <= ?", @start_date, @end_date).group_by(&:product_id)
  end