Php ile Cookie Kontrol

<?
$cookie=$_COOKIE['kullanici']; 
if($cookie==""){
echo "
<form action=\"gir.php\" method=\"post\" >
<label>Kullanici Adi : </label>
<input name=\"kul\" type=\"text\" /><br>
<label>Sifre : </label>
<input name=\"sif\" type=\"password\" /><br>
<input name=\"buton\" type=\"submit\" value=\"Login\" >
</form><br>
<a href=\"uyeol.php\">Register</a>* 
"; 
}
else{ 
$tarih=date("d/m/y"); 
echo "Hosgeldin $cookie | Suan Tarih $tarih "; 
} 
?>

<?
include "baglanti.php"; 
$kullanici=$_POST["kul"]; 
$sifre=$_POST["sif"]; 
if(($kullanici=="")or($sifre=="")){ 
echo "Lutfen Bos Alan Birakmayiniz"; 
}else{ 
$uyesor=mysql_query("select * from tkullanici where username='$kullanici' and sifre='$sifre'"); 
if(@mysql_num_rows($uyesor)>0){ 
echo "Hesabiniz acildi* 
Hosgeldiniz $kullanici 
"; 
setcookie("kullanici",$kullanici);
echo "Anasayfaya Donmek için <a href=index.php>Tıklayınız</a>"; 
}else{ 
echo "Başarısız Deneme"; 
} 
} 

?>

kullanici' OR sifre='

select * from tkullanici where username='kullanici' OR pass= '

<?php
$db = mysql_connect("localhost","root","");
mysql_select_db("targaf",$db);
$u = $_GET['u'];
$p = $_GET['p'];
$s = mysql_query("SELECT * FROM admin WHERE user='$u' AND pass='$p'");
echo ("SELECT * FROM admin WHERE user='$u' AND pass='$p'");
$q = mysql_fetch_array($s);
print_r($q);
?>