Warning: mysql_fetch_array(): ขึ้นว่า Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in

<?
$id_ques=$_GET[id_ques];

$sql="select * from question where id_ques='$id_ques' ";
$result=mysql_query($sql);
$record=mysql_fetch_array($result);

$id_ques=$record[id_ques];
$title_ques=$record[title_ques];
$detail_ques=$record[detail_ques];
$name_ques=$record[name_ques];
$email_ques=$record[email_ques];
$date_ques=$record[date_ques];

$title_ques=htmlspecialchars($title_ques);
$detail_ques=nl2br(htmlspecialchars($detail_ques));
$name_ques=htmlspecialchars($name_ques);
$email_ques=htmlspecialchars($email_ques);
$date_ques=displaydate($date_ques);

?>

<? echo "$detail_ques";?>