How do I redirect from my module if query fails?

[mccollin]

I am building a CMPS module that will let me dynamically build a page from GARS custom fields, so that I can have one page definition and generate hundreds of pages from it. I have it all working, but I need to now put in some error detection. I am passing a url value that is used to find the correct thread. If someone inputs a bogus value, then it takes me into a messy end result... here is the framework I am working with...

PHP Code:

$device = $vbulletin->input-clean_gpc('r', 'd', TYPE_NOHTML); 

$sql = "SELECT statement...  
          WHERE .... AND gcv.gars36 = '$device' "; 

$result = $db->query_read($sql);  

    while ($result = $db->fetch_array($results))
    {
 ..........
    } 


The value that is passed into $device is supposed to match one unique thread. If the value is bogus, nothing is found. How can I detect that I retrieved no rows and immediately redirect to another url without continuing the module?

Assuming I can do that, is there a way to also do the redirect if I return more than one row?