"NOT ONLY IN" taxonomy query operator?

Question

I have multiple users adding content to restricted categories (using RoleScoper) in my WordPress setup that don't show up on the homepage (custom template with query_posts()).

I'm looking for a way to "promote" the submitted content to the homepage by adding it to another category.

My loop code looks like this:

<?php
query_posts($query_string . '&cat=-37');
if (have_posts()):
    while (have_posts()): the_post(); ?>

This will exclude all posts in category 37. However, even if I add the post to a different category it still gets excluded.

Is there a way to exclude a post if it belongs to just that one category?

Answer 1

There is no simple way to do this via WP_Query(). Depending how many categories you have, the following may not be a good idea. If you have ~20 you may be ok. So, instead of saying "all posts excluding ones in 37", you would do "get me everything in all terms (not specifying term_id 37").

To do this you need to use a category__in for all your other categories:

// Get all the category IDs (except 37)
$categories = get_terms( 'category', array( 'exclude' => array( 37 ), 'fields' => 'ids' ) );

query_posts( array( 'category__in' => $categories ) );

This will get you all posts that are in a category other than/aswel as 37. However, doing this on a large amount of categories will start to slow the query down (I am thinking +40,000 posts for example).