Object reference not set to an instance of an object.SELECT An_Pham.NHOM_AN_PHAM, Max(An_Pham.ACTIVE) AS ACTIVE, Max(An_Pham.SAP_XEP) AS SAP_XEP FROM An_Pham WHERE (((An_Pham.ACTIVE)=1)) GROUP BY An_Pham.NHOM_AN_PHAM ORDER BY Max(An_Pham.SAP_XEP)