SQL Dotaz v Accessu

Zdravim, mam dotaz k SQL dotazum v Accesu.

Mam tabulku a napsal jsem nasledujici sql query

SELECT		Exposure_Class,
		Tranche_Type_Code,
		SUM(tranche_exposure)/1000+SUM(accrued_fees)/1000 AS Exposure_KCZK
FROM 	sm_kb_local_ratio
WHERE 	correction_flag = '1'
		AND date_valid = '2010-12-31'
		AND (inter_company ='F' OR inter_company IS NULL)
		AND default_indicator ='T' --- proč nepoužije custommer_evaluation?
		AND import_source = 'BCE'
GROUP BY tranche_exposure, accrued_fees
;

Hazi mi to chybu "you tried to execute a query that does not include the specified expression as part of an aggregate function"

Mam takovy pocit ze to je tim ze nektere pole v tranchee exposure a accrued fees jsou prazdne (ne nula).

Muze to byt tim? Pripadne EXISTUJE nejaka funkce v Accesu aby vzala napr IFNULL=0? nebo jak toto resit na urovni vystupu (nemuzu modifikovat zdrojova data)?

Diky