ник: Анатолий (Киев)
Еще вариант:
SELECT CAODealRegs.RegNumber, CAODocs.DocDate
FROM CAODealRegs LEFT JOIN CAODocs ON CAODealRegs.ID = CAODocs.DealReg
WHERE EXISTS (SELECT * FROM CAODocs As tmp WHERE ((tmp.DealReg=CAODocs.DealReg)
AND (Abs(Year(CAODocs.DocDate)-Year(tmp.DocDate))>=1));