$pid = $_GET['id'];
$index = mysql_query("SELECT * FROM index where id = '".$pid."'") or die(mysql_error());
$row = mysql_fetch_array($index);
$thisvar = $row['name'] . "x";
echo $thisvar; //Check here
$query = mysql_query("SELECT * FROM ".$thisvar." where uid = '".$_SESSION['id']."'") or die(mysql_error());
$row1 = mysql_fetch_array($query); 
$uid = $row1['id'];
echo $uid;