สอบถามเรื่อง Where ข้อมูล DATA/TIME ระหว่าง VC# กับ ACCESS หน่อยครับ

  private void getgv()
        {
            string stracc;
            stracc = "SELECT CHECKINOUT.CHECKTIME,CHECKINOUT.sn, USERINFO.SSN FROM USERINFO ";
            stracc += "Inner Join CHECKINOUT on CHECKINOUT.USERID = USERINFO.USERID ";
            stracc += "Where SSN = '" + cb_id.EditValue + "' Order By CHECKTIME asc ";
            ds = ojodbc1.GetDataSet(stracc, "data");
            gvhr_time.DataSource = ds.Tables[0];

            foreach (DataRow dr in ds.Tables[0].Rows)
            {
                strGVm = dr["CHECKTIME"].ToString().Substring(0, 2);
                strGVy = dr["CHECKTIME"].ToString().Substring(6, 4);
                strGV = strGVm + "/" + strGVy;
                dr["sn"] = strGV;
            }
 }
        private void getgv2()
        {
            string stracc2;
            stracc2 = "SELECT CHECKINOUT.CHECKTIME,CHECKINOUT.sn, USERINFO.SSN FROM USERINFO ";
            stracc2 += "Inner Join CHECKINOUT on CHECKINOUT.USERID = USERINFO.USERID ";
            stracc2 += "Where SSN = '" + cb_id.EditValue + "' and sn = '" + strmldr + "' Order By CHECKTIME asc ";
            ds2 = ojodbc1.GetDataSet(stracc2, "data");
            gvhr_time.DataSource = ds2.Tables[0];
        }