Suppose you have multiple BAR databases (BAR.DB1 and BAR.DB2, for instance). When you run an NPR Report, you are prompted to select one of those BAR databases.
You can, however, modify your report to include data from ALL of your BAR databases.
For MAGIC sites, simply add MIS.APPL.multi-database as a Sort Field. For C/S sites, add MIS.APPL.DB.multi.db as a Sort Field. When you translate your report, you will see a message like this: This is a multi-database report.
This works not just for BAR but for any application with multiple databases.