Scusa ma non ancora molto pratico di php

Prova a vedere se riesci a comprendere così:

$params="?posted=1";
foreach($_REQUEST as $key=>$value){
$$key=$value;
$params.=($key=="PHPSESSID")?"":"&".$key."=".$valu e; // block session id
}
if (!$posted) {
$redirect=$_SERVER["PHP_SELF"].$params;
header("Location: $redirect"); /* Redirect browser */
return;
}

header5("$lang[aucsearch]");

if ($_REQUEST['orderField']=="") $orderField = "enddate";
else $orderField=$_REQUEST['orderField'];
if ($_REQUEST['orderType']=="") {
$orderType = "ASC";
$newOrder="DESC";
} else {
$orderType=$_REQUEST['orderType'];
$newOrder=($orderType=="ASC")?"DESC":"ASC";
}

if (isset($_REQUEST['itemsearchok'])||$_GET['advsrc']=="itemsearch") {
$advsrc = "itemsearch";
$query = "SELECT * FROM annunci WHERE keywords LIKE '%".$_REQUEST['keywords']."%' AND deleted!=1 AND active=1 ";
if ($_REQUEST['category']!=0) $query .= " AND category='".$_REQUEST['category']."'";
if ($_REQUEST['bnonly']=="yes") $query .= " AND bn='Y'";
if ($_REQUEST['rponly']=="yes") $query .= " AND rp='Y'";
if ($_REQUEST['dutchonly']=="yes") $query .= " AND auctiontype='dutch'";
if ($_REQUEST['results']==2) $query .= " AND closed=0";
if ($_REQUEST['results']==3) $query .= " AND closed=1";
if ($_REQUEST['country']!="all") $query .= " AND country='".$_REQUEST['country']."'";
if ($_REQUEST['listin']=="auction") $query .= " AND listin!='store'";
else if ($_REQUEST['listin']=="store") $query .= " AND listin!='auction'";

if (trim($_REQUEST['zip'])!="") $query .= " AND zip LIKE '%".$_REQUEST['zip']."%'";
if (!$_REQUEST['orderField']) {
if ($_REQUEST['sortby']==1) {
$orderField = "enddate";
$orderType = "ASC";
}
if ($_REQUEST['sortby']==2) {
$orderField = "startdate";
$orderType = "DESC";
}
if ($_REQUEST['sortby']==3) {
$orderField = "bidstart";
$orderType = "ASC";
}
}
} else if (isset($_REQUEST['usersearchok'])||$_GET['advsrc']=="usersearch") {
$advsrc = "usersearch";
$query = "SELECT DISTINCT auct.id, auct.picpath, auct.itemname, auct.maxbid, auct.nrbids, auct.currency, auct.enddate,
auct.bidstart, auct.bn, auct.bnvalue, auct.zoom, auct.accept_payment_systems FROM
users AS users, annunci AS auct WHERE
(users.username LIKE '%".$_REQUEST['keywords']."%')
AND users.id=auct.ownerid AND auct.deleted!=1 AND auct.active=1";

if ($_REQUEST['results']==2) $query .= " AND auct.closed=0";
if ($_REQUEST['results']==3) $query .= " AND auct.closed=1";

if (!$_REQUEST['orderField']) {
if ($_REQUEST['sortby']==1) {
$orderField = "auct.enddate";
$orderType = "ASC";
}
if ($_REQUEST['sortby']==2) {
$orderField = "auct.startdate";
$orderType = "DESC";
}
if ($_REQUEST['sortby']==3) {
$orderField = "auct.bidstart";
$orderType = "ASC";
}
}
} else if (isset($_REQUEST['buyersearchok'])||$_GET['advsrc']=="buyersearch") {
$advsrc = "buyersearch";
$query = "SELECT DISTINCT auct.id, auct.picpath, auct.itemname, auct.maxbid, auct.nrbids, auct.currency, auct.enddate,
start, auct.bn, auct.bnvalue, auct.zoom, auct.accept_payment_systems FROM
users AS users, annuncio AS auct, bids AS bid WHERE
(users.username LIKE '%".$_REQUEST['username']."%')
AND users.id=bid.bidderid AND auct.id=bid.auctionid AND auct.deleted!=1 AND auct.closed=0 AND auct.active=1 ";
} else {
$query = "SELECT * FROM annunci
WHERE (lcase(keywords) LIKE lcase('%".$_REQUEST['basicsearch']."%') OR ucase(keywords) LIKE ucase('%".$_REQUEST['basicsearch']."%')) AND active=1 AND closed=0 AND deleted!=1";
}

$additionalVars = "&basicsearch=".$_REQUEST['basicsearch']."&advsrc=".$advsrc.
"&results=".$_REQUEST['results']."&sortby=".$_REQUEST['sortby'].
"&keywords=".$_REQUEST['keywords']."&country=".$_REQUEST['country'].
"&bnonly=".$_REQUEST['bnonly']."&rponly=".$_REQUEST['rponly']."&dutchonly=".$_REQUEST['dutchonly']."&username=".$_REQUEST['username']."&listin=".$_REQUEST['listin'];
if ($_GET['start'] == "") $start = 0;
else $start = $_GET['start'];
$limit = 20;

$totalResults = getSqlNumber($query." ORDER BY ".$orderField." ".$orderType."");
$resultsQuery = mysql_query($query." ORDER BY ".$orderField." ".$orderType." LIMIT ".$start.",".$limit."");
?>