Exemple

admin.php

<?php
session_start();

if (!isset($_SESSION['id'])) {
    
    header('Location: connexion.php'); # Si le membre est pas connecté, on le redirige vers la connexion.php

} elseif (isset($_SESSION['id']) && $_SESSION['grade'] != 'administrateur') {
    
    header('Location: index.php'); # Si le member est conencté, mais il est pas administrateur, on le redirige vers index.php
}

$bdd = new PDO('mysql:host=127.0.0.1;dbname=espace_membre;charset=utf8', 'root', '');
if (isset($_POST['id'], $_POST['ban'], $_POST['secure'])) {
    $id = intval($_POST['id']);
    $request = $bdd->prepare('UPDATE membres SET ban = ? WHERE id = ?');
    if ($request->execute([$_POST['ban'], $id])) {
        $message = 'Membre ' . $_POST['ban'] === '0' ? 'banni' : 'dé-banni';
        $_SESSION['flash'] = $message;
        header('Location: admin.php');
    }
}
$members = $bdd->query('SELECT * FROM membres');
if (!empty($_SESSION['flash'])): 
    echo $_SESSION['flash'];
    unset($_SESSION['flash']);
endif; ?>
<table>
    <thead>
        <tr>
            <th>Id</th>
            <th>Pseudo</th>
            <th>Mail</th>
            <th>Grade</th>
            <th>Action</th>
        </tr>
    </thead>
    <tbody>
        <?php foreach ($members as $member): ?>
        <tr>
            <td><?= $member['id'] ?></td>
            <td style="font-weight:bold;"><?= $member['pseudo'] ?></td>
            <td><?= $member['mail'] ?></td>
            <td><?= $member['grade'] ?></td>
            <td>
                <form method="POST">
                    <input type="hidden" name="id" value="<?= $member['id'] ?>">
                    <input type="hidden" name="ban" value="<?= $member['ban'] === '0' ? '1' : '0' ?>">
                    <input type="checkbox" name="secure">
                    <button type="submit"><?= $member['ban'] === '0' ? 'Bannir' : 'Dé-bannir' ?></button>
                </form>
            </td>
        </tr>
        <?php endforeach; ?>
    </tbody>
</table>