[paulmjno]

Mwahaha! I've done it. Easy peasy. I'll post some code here - I'm not really one for writing scripts for other people (with the random problems people run into), but this should assist someone else (I've used the ezSQL class here):

PHP Code:

<?php

include_once("db.php");

$threads = $db->get_results("SELECT threadid, threadprefix FROM thread");

foreach ($threads as $thread) {
    if ($thread->threadprefix) {
        $db->query("UPDATE thread SET prefixid = '" . strtolower($thread->threadprefix) . "' WHERE threadid = $thread->threadid");
    }
    print "Done threadid: {$thread->threadid}<br />";
}

?>

What I've done is pre-created the native thread prefixes matching the ones I currently use.