ACCESS SQL查询无法在PHP中运行

Question

i have sql query it works with select * but when i put column names it does not show data.

$sql2="SELECT PSO_NAME, PSO_SIGNATURE, PSO_DATE FROM SIGNATURES_DASO WHERE DASO_NO ='".$daso_no."'";
echo $sql2; //it shows the query which i tested in access runs fine.
$rs_pso_sign=odbc_exec($conn,$sql2);
if (!$rs_pso_sign) {
  exit("Error in SIGNATURE TABLE INFO SQL");
}

if(odbc_fetch_row($rs_pso_sign)){

                $psoName = odbc_result($rs_pso_sign, "PSO_NAME");
                $psoSign = odbc_result($rs_pso_sign, "PSO_SIGNATURE");
                $psoDate = odbc_result($rs_pso_sign, "PSO_DATE");
                echo $psoName;
         }
else
 {
 echo "$psoName does not exist";
}

it works when i do

 $sql2="SELECT * FROM SIGNATURES_DASO WHERE DASO_NO ='".$daso_no."'";

i checked from database column names are the same no typo mistake as well.

any suggestions?