Negate RESULT SET, All Inactive Client

I' d like to list all inactive clients.
Inactive client is a client who hasn't had invoice for 2 months.

I use INNER JOIN to join invoice view (vwDok4FSFZGrid) and clients
addresses table (adr_Nazwa). I skip empty values (adr_Ewid.adr_Nazwa !
=''). I select only invoices with date after the interesting date.

So now I can list all active clients but i can't negate this result
set to get all inactive clients:

SELECT dok_PlatnikId, adr_Nazwa,
adr_NazwaPelna,adr_Adres,adr_Miejscowosc,adr_NIP, dok_DataWyst
FROM vwDok4FSFZGrid
INNER JOIN adr__Ewid
ON vwDok4FSFZGrid.dok_PlatnikId=adr__Ewid.adr_IdObiek tu
WHERE
adr__Ewid.adr_Nazwa !=''
AND
(dok_DataWyst >= convert(datetime,'10/03/2007'))
GROUP BY dok_PlatnikId, adr_Nazwa,
adr_NazwaPelna,adr_Adres,adr_Miejscowosc,adr_NIP, dok_DataWyst

Is there any way to negate this set?

1. Sorry for my English
2. I would appreciate any help
:)