Select Center, (SELECT Center, SUM(qdfPayments.IncomePaymentSumCalc)  FROM qdfPayments
 WHERE Year(PaymentDate)<=2015 AND Center<>''  
GROUP BY Center) + SUM(qdfPayments.IncomePaymentSumCalc *( -(Month(PaymentDate) = 1))) AS Январь   FROM qdfPayments WHERE  Year(PaymentDate) <= 2015 AND Center<>'' 
GROUP BY Center

http://www.sql.ru/forum/1199916/sql-access-kak-summirovat-podzaprosy