不同课程邮件多条记录按desc排序

app/models/mailer.rb

@@ -124,8 +124,8 @@ class Mailer < ActionMailer::Base
         attachments = courses[i].attachments.where("attachments.created_on between '#{date_from}' and '#{date_to}'").order('attachments.created_on DESC')
         @bids += bids if bids.count > 0
         @attachments += attachments if attachments.count > 0
-
       end
+      @bids.sort {|a, b| a.created_at <=> b.created_at}
     end
 
     # 项目附件