// this is the code
if($conn) {
    if ($_SERVER["REQUEST_METHOD"] == "POST") {
        $just = $_POST["just"];
        $sql_ref = "UPDATE adopteur
        SET etat_demande = 'acceptee', explication = '{$just}'
        WHERE id_adopteur = {$id_adopteur}";
        // executer la requete
        $query = mysqli_query($conn,$sql_ref);
        if($query) {
            echo "<script>confirm('updated')</script>";
            header("location:$url");
        }
        else {
            echo "<script>confirm('not updated')</script>";
        }
    }
}
// this is the error i get
Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'accepte cette demande parceque je suis entrain de tester' WHERE id_a...' at line 2 in C:\xampp\htdocs\adoption_website\info_demand_accepte.php:15 Stack trace: #0 C:\xampp\htdocs\adoption_website\info_demand_accepte.php(15): mysqli_query(Object(mysqli), 'UPDATE adopteur...') #1 {main} thrown in C:\xampp\htdocs\adoption_website\info_demand_accepte.php on line 15