I can't seem to correctly iterate through the rows of a db query. Am i doing something wrong with the below example?

try {
    $posts = \IPS\Db::i()->select('*', 'forums_posts', array('topic_id=?', $topic))->first();
}
catch( \UnderflowException $e ) {
    // Query failed
}

foreach ( $posts as $post ) {
	// not working?
}

 

$posts = \IPS\Db::i()->select('*', 'forums_posts', array('topic_id=?', $topic));

foreach ( $posts as $post ) {
	// not working?
}

->first() will get you the first matching record, and will throw an exception if nothing is to be found. this way, there is no exception throw, it just wont have anything or iterator over.