Outputting individual sql dialogs?

Question

PHP

There is a table 'message' (photo below)
What needs to be done is to display a dialog with a dialog column column:
sender id, recipient id.
Here is my output code.
but WHERE doesn't work..

<?php
require_once 'core/connect.php';
$to = $_GET['sel'];
$sender = $_SESSION['user']['id'];
$query = mysqli_query($connect, 
"SELECT
m.id_sms, m.dialog, u.name as id_sender, m.message, m.id_recipient, m.time
FROM messages m 
LEFT JOIN users u ON m.id_sender = u.id WHERE dialog = '$sender,$to' OR '$to,$sender'
ORDER BY m.time ASC

");
while ($result = mysqli_fetch_array($query)) {
echo 
'
html..
'; 
}
?>

Answer 1

Your table is not designed correctly. To solve the problem, the dialog field is not needed, it is enough to set the condition WHERE id_sender = $sender AND id_recipient = $to.

Answer 2

Replace with
WHERE dialog = '$sender,$to' OR '$to,$sender'

WHERE id_sender = $sender AND id_recipient = $to OR id_sender = $to AND id_recipient = $sender