when you subsequently call do_placeholder_query with the supplied variable array, the routine will replace the ?'s from the variables in the array..

example:
PHP Code

$queryVars = array($Board,$user['USER_ID']);
$query = "
			SELECT USER_ID
	FROM   {$config['TABLE_PREFIX']}MODERATORS
	WHERE  FORUM_ID = ?
	AND	USER_ID = ?
		";
$sth = $dbh -> do_placeholder_query($query,$queryVars);

soooo... $Board -- forum number -- goes in the first ? and $user['USER_ID'] -- goes in the second ? and THEN the query gets executed..

it can be done another way too... (your choice what you like, really)..

PHP Code
$query = "
			SELECT USER_ID
	FROM   {$config['TABLE_PREFIX']}MODERATORS
	WHERE  FORUM_ID = {$Board}
	AND	USER_ID = {$user['USER_ID']}
		";
$sth = $dbh -> do_query($query);

badabing smile