id barang baru

<?php
function autono($namabarang="barangku"){
$isi=mysql_query("select count(idbarang) tot from barang ") or die(mysql_error());
$dt=mysql_fetch_array($isi);
$num=$dt['tot']+1;
$idbarang=sprintf("%s%05s",
strtoupper($namabarang)[0],
$num;
return $idbarang;
}