What's Wrong With My Code?

[noonespecial]

$entry['tags'] has some "null" data ... would that cause a problem?

PHP Code:

$entry = $db->query_first("SELECT tags FROM " . TABLE_PREFIX . "journal_entries WHERE journal_id =" . $vbulletin->GPC['j']." AND tags IS NOT NULL"); 


EDIT: only pulls one entry from the correct row ... not all of them.

should i be doing a "query" instead -- and then grabbing the data out of the array a different way?