PHP MySQL prepare examples

$ruum_like = "%{$ruum}%";    
$stmt->bind_param("sss", $end, $start, $ruum_like);


$stmt = $db->prepare("SELECT ... WHERE field = ? AND field2 LIKE ?");
$stmt->bind_param("ss", $val1, $val2);
$stmt->execute();
$result = $stmt->get_result();
while ($mytable = $result->fetch_assoc()) {}

$my_code = '1234';
$now = date('Y-m-d H:i:s');
$empty_set = '0000-00-00 00:00:00';
$mail = '';


try{
  $sql = "INSERT into mus_kalender_jrk (rfid, date1, date2, mail) values (?, ?, ?, ?)";
  $stmt = $db->prepare($sql);
  $stmt->execute([$my_code, $now, $empty_set, $mail]);
            
        } catch(PDOException $e) {
         echo "Error: " . $e->getMessage();
    }