Почему так???

<?php
$connect=mysql_connect("127.0.0.1","","") or die('Can\'t connect');
mysql_select_db("tests") or die('No databases');
session_start();
$userid=14;
$zapros=mysql_query ("select name from users where userid=$userid");
$_SESSION=mysql_fetch_array($zapros);
echo 'wellcome'.$_SESSION['name'];
mysql_close();
?>
<a href="session2.php"> a </a>

<?php
session_start();
echo "еще разок wellcome ".$_SESSION['name'];
?>

$_SESSION=mysql_fetch_array($zapros);
echo 'wellcome'.$_SESSION['name'];

$mas=mysql_fetch_array($zapros);
$_SESSION['name']=$mas['name'];
echo 'wellcome'.$_SESSION['name'];

<?
function test() {global $var; $var=12345; }
test();
echo $var;
?>