I have basically copied that code from a tutorial. Why would it return empty results for $day and $visitors when there are values in db?
$db = mysql_connect("localhost", "root", "root");
mysql_select_db("webstats",$db);
$query = "SELECT * FROM stats";
$result = mysql_query($query,$db);
extract(mysql_fetch_array($query)); {
echo "<set name='$day' value='$visitors' color='FF5904' />";
}