PHP mysqli_multi_query () function

<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

$sql = "SELECT Lastname FROM Persons ORDER BY LastName;";
$sql .= "SELECT Country FROM Customers";

// Execute multi query
if (mysqli_multi_query($con,$sql))
{
do
{
// Store first result set
if ($result=mysqli_store_result($con))
{
while ($row=mysqli_fetch_row($result))
{
printf("%sn",$row[0]);
}
mysqli_free_result($con);
}
}
while (mysqli_next_result($con));
}

mysqli_close($con);
?>