Php Mysqli到SQLSRV选择函数

我有一个函数，它使用mysqli执行一个准备好的语句Select，但现在我希望它也能在sqlsrv上工作。我试图根据PHP手册修改一些代码，但无法使其正常工作

function selecless($query){

// THIS IS THE SQLSRV CONNECTION AND IT WORKS FINE

$serverName = "PC1337\SQLEXPRESS"; //serverName\instanceName
$connectionInfo = array( "Database"=>"DBX", "UID"=>"sa", "PWD"=>"as");
$conn = sqlsrv_connect( $serverName, $connectionInfo);

if( $conn ) {
     echo "Connection established.<br />";
}else{
     echo "Connection could not be established.<br />";
     die( print_r( sqlsrv_errors(), true));
}

// THIS IS THE MYSQLI CODE THAT I WANT TO CONVERT TO SQLSRV

$res = $conn->prepare($q);
$res->execute();
$meta = $res->result_metadata();
while( $field = $meta->fetch_field() ) {
                    $parameters[] = &$row[$field->name];
                }
call_user_func_array(array($res, 'bind_result'), $parameters);
while($res->fetch()){
foreach($row as $key => $val ) {
    $x[$key] = $val;
}
$resultado[] = $x;
}
if (isset($resultado) == false) {
return '';
}else{
return $resultado;
}
$res->close();
$conn->close();

}

$resp = selecless("select col1 from table");
            if (empty($resp) == false){
            $value = $resp[0]['col1'];
            echo $value;
            }else{
            echo 'null';
            }