PHP MSQL รบกวนดูโค้ดเกี่ยวกับการโหวตให้คะแนนกระทู้หน่อยค่ะ

<? session_start();
	if($_SESSION['user_id'] == "")
		{
		echo "<script> alert (' please LOGIN !!') ;</script>";
		echo"<meta http-equiv=\"refresh\" content=\"0;url='login.php'\">";
		exit();
		}
	if($_SESSION['status'] != "0")
		{
		echo "<script> alert ('This page for admin only') ;</script>"; 
		echo"<meta http-equiv=\"refresh\" content=\"0;url='login.php'\">";
		exit();		
		}
		
		?> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />


		
	<? include("connect.php");


$sql = "select * from vote where question_id = '".$_GET['questionid']."' and user_id = '$user_id' ";
$dbquery=mysql_db_query($db,$sql);
$queryC = mysql_fetch_array($dbquery);


$sql3 = "select * from vote inner join webboard_post on vote.question_id = webboard_post.question_id and vote.user_id = webboard_post.user_id  ";
$dbquery3=mysql_db_query($db,$sql3);
$queryC3 = mysql_fetch_array($dbquery3);
$numC	= mysql_num_rows($queryC);

if ($numC != 0)// ถ้า username มีการใช้งานไปแล้ว จะมีการแจ้งเตือนให้เปลี่ยน
{
	echo "<script> alert (' คุณโหวตหัวข้อนี้ไปแล้วค่ะ ') ; history.back();</script>";
	exit ();

}
//$vote_count = 0;

$sql1 = "insert into vote (vote_id , question_id , user_id  , vote_count) VALUES ('','".$_GET['questionid']."','$user_id','$vote_count')  ";
$dbquery1=mysql_db_query($db,$sql1);


if ($question_id!=$question_id || $user_id!=$user_id)
	{
		echo "<script> alert ('คุณโหวตให้หัวข้อนี้ไปแล้วค่ะ') ; history.back();</script>";
 		exit();
	}

	
$vote_count = $queryC['vote_count']+1;
$sql2="update vote set vote_id='' ,  vote_count='$vote_count' where question_id = '".$_GET['questionid']."' ";

$dbquery2=mysql_db_query($db,$sql2);
echo "<script> alert (' คุณโหวตให้กับหัวข้อนี้เรียบร้อยแล้วค่ะ ') ; history.back();</script>";

//mysql_close();

	


?>