Set to 0 when product price base is null

app/controllers/reports_controller.rb

@@ -80,7 +80,7 @@ class ReportsController < ApplicationController
         @total_prods += sale.sales_details.sum(:quantity)
         cost = 0
         sale.sales_details.each do |detail|
-          cost += (detail.product.price_base * detail.quantity)
+          cost += !detail.product.price_base.nil? ? (detail.product.price_base * detail.quantity) : 0
         end
         utility = sale.total - cost
         @total_utility += utility

app/helpers/sales_helper.rb

@@ -26,7 +26,7 @@ module SalesHelper
   def sale_utility(details)
     total = 0
     details.each do |detail|
-      total += (detail.product.price_base * detail.quantity)
+      total += !detail.product.price_base.nil? ? (detail.product.price_base * detail.quantity) : 0
     end
     total
   end