priting random values from mysql

<?php
$link = mysqli_connect("localhost", "root", "1124", "mini_dialer");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}
$rand=array();

$query = " select * from  leads";

if ($result = mysqli_query($link, $query)) {

    /* fetch associative array */
    while ($row = mysqli_fetch_assoc($result)) {
        $rand[]=$row[lead_id];

   }

    /* free result set */
    mysqli_free_result($result);

 $key=array_rand ($rand);
 echo "Selecting random element  $rand[$key]"; // this will print rand  value

}


else {mysqli_close($link);
?>


 printf("Error: %s\n", mysqli_error($link));

}


/* close connection */