You can limit the scope of selections. For example, you have a file that relates to an entire entity, but you want to examine only one portion of it, such as “Department 13.” In this case, you can add the condition IF DEPT='13' to the sample to limit the scope of the selection.
Or you can ignore certain types of transactions such as postings from “AP.” In this case, you can specify a test, such as IF SOURCE<>'AP'.