```
 $elements = $xpath->query(
   "//message[(@sender ='".$from." and @receiver = '".$username."') or
   (@receiver='unread' and @sender = '".$username."')]"
  );

```

Whats the problem with this code?
I need something like this `SELECT data WHERE ((sender == from AND receiver = username)OR(sender == username AND receiver = from))` from my xml file