[Modin]

as far as I know you can't do it in a single query, you'll need a quick script.

PHP Code:

<?php
require('global.php');

$threads = $DB_site->query("SELECT threadid, title FROM " . TABLE_PREFIX . "thread");
while($thread = $DB_site->fetch_array($threads))
{
    $DB_site->query("UPDATE YourTable SET title='$thread[title]' WHERE threadid='$thread[threadid]'");
}
echo "Script Done";
?>

Hopefully that works for ya