SESSION Loop that increments counter - php

Question

My session checks if a user is logged , however when I refresh the page the session test runs again and starts to execute the code which then adds +1 to the members online counter everytime . I would like my code to check if the session is true like below but not if I refresh the page or navigate to another page .(Only Once per login) How can this be possible ?
PS MY code is not secure My code is not in any live environment , Security will be applied later to prevent sql injection .
include('..\db.php');
$con = mysqli_connect($dbsrvname, $dbusername, $dbpassword, $dbname);
$guest_timeout = time() -1 * 60;
$member_timeout = time() -2 * 60;
$guest_ip = $_SERVER['REMOTE_ADDR'];
$time = time()
// This session check adds +1 to my member online counter when page is reloaded
if(isset($_SESSION['CurrentUser'])){
//if user is logged
$sqlt = mysqli_query($con,"DELETE * FROM active_guests WHERE guest_ip='".$guest_ip."'");
$sqlt2 = mysqli_query($con,"REPLACE INTO active_members VALUES ('".$_SESSION['CurrentUser']."','".$time."')");
}else{
//if user not logged
$sqlt3 = mysqli_query($con,"REPLACE INTO active_guest (guest_ip,time_visited)VALUES ('".$guest_ip."','".$time."')");
}
$sqlt4 = mysqli_query($con,"DELETE * FROM active_guest WHERE time_visited < ".$guest_timeout);
$sqlt5 = mysqli_query($con,"DELETE * FROM active_members WHERE time_visited < ".$member_timeout);
$sqlt6 = mysqli_query($con,"SELECT guest_ip FROM active_guests");
$online_guests = mysqli_num_rows($sqlt6);
$sqlt7 = mysqli_query($con,"SELECT username FROM active_members");
$online_members = mysqli_num_rows($sqlt7);
?>
<div class="container">
<p>online Guests : <?php echo $online_guests ; ?></p>
<p>online Members : <?php echo $online_members ; ?></p>
</div>

Answer 1

You need a unique index on the username column so that REPLACE will replace instead of inserting a duplicate row.
ALTER TABLE active_members ADD UNIQUE INDEX (username);
You probably also need a unique index on the guest_ip column of active_guests, although it's possible that multiple users could be coming from the same IP.