de id opzoeken via tekstveld

<?php $id = mysql_real_escape_string($_GET['id']); ?>

<?php
if(isset($_POST['submit']))
{
	$naam = mysql_real_escape_string($_POST['naam']);
	$sort = mysql_real_escape_string($_POST['sort']);
	$genre = mysql_real_escape_string($_POST['genre']);
	if(intval($_GET['id'])) {
	$id = mysql_real_escape_string($_GET['id']);
	}
	else {
	$artiest = mysql_real_escape_string($_POST['artiest']);
	$id = mysql_real_escape_string($_GET['id']); 
    $sql = "
	SELECT id 
	FROM artiesten
	WHERE artiest=".$artiest."
	";
	}

	$songtekst = mysql_real_escape_string($_POST['songtekst']);

$sql = "INSERT INTO liedjes
       (naam, sort, genre, favoriet, profiel, position, artiestnaam, songtekst, mp3 ) 
       VALUES('$naam', '$sort', '$genre', 'nee', 'nee', '', '$id', '$songtekst', '$naam') 
	   ";
$retval = mysql_query( $sql, $mysql_connect );
if(! $retval )
{
  die('FOUT ' . mysql_error());
}
?>

<a href="http://web-stars.nl/muziek/artiest.php?id=<?php echo $_GET['id']; ?>" style="color:#000000;">gelukt <br /> klik hier om naar de artiest te gaan</a> 

<?php
}
else
{
?>
<div class="row">
<div class="col-md-5">
<form method="post" action="<?php $_PHP_SELF ?>">

<div class="form-group">
    <label for="naam">liedjes naam</label>
  <input type="text" name="naam" class="form-control" id="naam">‏
  </div>   
 

<div class="form-group">
    <label for="sort">sorteren op alfabet als eerste letter van liedjesnaam</label>
  <input type="text" name="sort" class="form-control" id="sort">‏
  </div>  
  
<div class="form-group">
    <label for="genre">genre</label>
  <input type="text" name="genre" class="form-control" id="genre" >‏
  </div> 

  <?php 
  if(intval($_GET['id'])) {
  }
  else {
	  ?>
  <div class="form-group">
    <label for="artiest">artiest</label>
  <input type="text" name="artiest" class="form-control" id="artiest" >‏
  </div> 
  <?php }
  ?>