$kullanicisor=$db->prepare("SELECT * FROM user WHERE username=:username");
$kullanicisor->execute(array(
'username'=>$_GET['user']
));
$say=$kullanicisor->rowCount();
$kullanicicek=$kullanicisor->fetch(PDO::FETCH_ASSOC);
if ($say==0) {
header("Location:index.php?kullanici=yok");
exit;
}