order base detail export edit

app/models/order_base_detail.rb

@@ -15,9 +15,11 @@ class OrderBaseDetail < ActiveRecord::Base
 
   def paid_time
     paidTime = 0
-    order = Order.where("id = ?", self.order_id).first
-    if !order.blank?
-      paidTime=order.paied_at.to_i
+    if self.order_id>0
+      order = Order.where("id = ?", self.order_id).first
+      if !order.blank?
+        paidTime=order.paied_at
+      end
     end
     return paidTime
   end