Sample code for 'Search Joins'?

Hi,

We have a requirement at one of our customer’s implementation to download Sales Order from NetSuite into a different application. We created a custom List Type field 'Downloaded' with 3 values - Edit, Success, Fail. By default, all the orders are in Edit mode when created. All the orders which are downloaded to the application are marked with Success and the orders which fail due to configuration issue in the application (e.g., Item does not exists) are marked with Fail.

We run a scheduler (windows scheduler) to download the orders every half an hour using webservices. There are hundreds of orders every day so when downloading we would like to check the orders only which are either Edit or Fail. One way is to check all orders for the status and then download them, but this takes a lot of time (performance issue). Is it possible to filter the orders based on this custom field 'Downloaded' and not check all the orders but only the ones which are Edit or Fail.