MySQL根据填充的组合框值擦除一行

I'm trying to delete a row in mysql based on the selection I make in a combox, I know this is deprecated but it's just for personal use. By the way I have something like this:

<form method="get" action="">
<?
require ('link.php');
mysql_select_db('proesi',$link) or die(mysql_error());
$rs = mysql_query("SELECT * FROM curso") or die(mysql_error());
echo "<select name='combo'>";
while($row2 = mysql_fetch_array($rs)){
echo "<option value='".$row2["id"]."'>".$row2["curso"]."</option>";
}
echo "</select>";

?>
<input type="submit" name="borrar" value="ELIMINAR"  />
</form>
<?
$combos = $_get['combo'];
if (isset ($_post['borrar'])){
    print $combos;
    require ('link.php');
        mysql_select_db('proesi',$link) or die(mysql_error());
        mysql_query("DELETE FROM curso WHERE curso= //here i need to get the value, i'm trying to use the "id" field since it is unique// ") or die (mysql_error());
        mysql_close($link);

    }
?>

the select has a name. When the form is submitted, you can get it's value with $_GET['combo']

Then, in your sql,

$selected_id = $_GET['combo']; //sanitize this!!!
mysql_query("DELETE FROM curso WHERE curso= '$selected_id' ") or die (mysql_error());

of course you have to make sure the value entered into the sql is sanitized and secure from sql injections, but since you are learning, you will get to it later.