Many thanks for your reply.

And yes it s not possible to normalize as the data come from pdf captured areas from invoices.

Each invoices could have 40 services it s depend how many purchase order are booked on it.

And the ’null’ result correspond to a normal situation .

The service code show a discrepencie between the PO and the invoice.

So the manager need to received it and approved . So if he had 10 discrepencies he just need to received the document once.

That why i need to remouving duplicates by invoices...