<?php 
    $sn=$_GET['sn'];
    $query="SELECT * FROM `banner_ad` WHERE `banner_no`='$sn'";
    if($query_run=mysql_query($query))
    {
        $num=mysql_num_rows($query_run);
        if($num == 1)
        {
            while($rows=mysql_fetch_array($query_run))
            {
                $banner_name=$rows['banner_name'];
                //$banner_site_url=$rows['Banner_website_url'];
                $banner_image_url=$rows['banner_image_url'];
            }
        } else {
            echo'<font color="red"> There is two entry for this same serial number.</font>';
            }
    } else {
        echo'<font color="red"> Query does not run.</font>';
        }
?>
このクエリを実行できない理由を誰か教えてもらえますか?