if(isset($_POST['submit']) AND $user_id == 1){
mysql_query('UPDATE `mp_player` SET `sostav` = '.$_POST['sostav']);
}
if($user_id == 1) {
echo '<select name = "sostav">
<option value = "0">Зап</option>
<option value = "1">Осн</option>
</select>';
}