güncelleştirme sorgusu için aşağıdaki kodu dener misiniz?
UPDATE (SELECT REC_RECETELER.RENK_NO, REC_RECETELER.MUSTERI, Mid([RENK_NO],InStr([RENK_NO],"-")+1) AS RnkN
FROM REC_RECETELER) AS Rct INNER JOIN (SELECT RENK_NO.RENK_NO, RENK_NO.MUSTERI, Mid([RENK_NO],InStr([RENK_NO],"-")+1) AS RnkN
FROM RENK_NO
WHERE (((RENK_NO.RENK_NO) Like "BL-*"))) AS Rnk ON (Rct.MUSTERI = Rnk.MUSTERI) AND (Rct.RnkN = Rnk.RnkN) SET Rnk.RENK_NO = [Rct]![RENK_NO];