SAP query report - using conditions

Hi

I have a created a query joing 3 tables EKKO,EKBE and custom table with purchase order, article and qty fields.

I want to create a discrepancy report :

1. Display records where EKBE qty (GI qty) and qty (GR qty) in custom table are not equal.

2. Custom table may have some dummy PO numbers( not existing in EKKO). How to pull them in the report?

Since PO numbers are key fields in all tables and joined, any PO number which exists in custom atble but does not exists in

ekko table doesn't appear in the report.

Any input will be highly appreciated.

Thanks

Sanjay