如何在选择框选项更改（php）上更新mySQL数据库？

Question

I have a selectbox which should update my SQL database by option change. Because in this case I do not have a normal submit input field, if(isset($_GET['submit']))is not working, but I do not know how to write the statement in the right way:

<?php
if(isset($_GET['submit'])){
    $status = $_GET['status'];
    $id = $_GET['id'];
        $pdo = Database::connect();
        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        $sql = "UPDATE colors set status = ? WHERE id = '$id'";
        $q = $pdo->prepare($sql);
        $q->execute(array($status));
        Database::disconnect();
}
?>      

                    <form action="index.php" method="get">
                        <select name="status" onchange='this.form.submit()'>
                        <option value="red">red</option>
                        <option value="blue">blue</option>
                    </select>
<?php echo "<input id='id' type='hidden' value='"$id"'>";?>
</form>

Answer 1

It could be as simple as

if(!empty($_GET['status'])){
   ....
}