Query posts that have only one custom taxonomy term WordPress

mackrider comments:

Theoretically yes, but not the category taxonomy - the artist_tag taxonomy.

Give me all posts that have the artist_tag of "the-doors" AND HAVE NO OTHER artist_tag taxonomies besides "the-doors"

Thanks

Michael Caputo comments:

I'm trying to find an easy solution, but coming up short.

Could you maybe come at it from the other angle and exclude all non associated terms?

mackrider comments:

What do you mean?

Michael Caputo comments:

Instead of writing a query that says

Only include term A

write one that says

Exclude B, C, D, E, F, G, H.....

mackrider comments:

Yeah but that could get expensive, no? It would have to be dynamic -- basically would have to get all artist_tags and then exclude them on the fly.

I could imagine that would get fairly pricey... give it a shot and I can test it.

Michael Caputo comments:

I'd suggest using a caching plugin on your site if you were going to go that route... I don't have time to write this up right now unfortunately, I can take a look later on though

mackrider comments:

I'd prefer that way - but if that is the way to do it then that's fine.

Hai Bui comments:

Try the code below. I suggest using term id instead of the term slug because term slug would require another table (= another join) and it'd be more expensive, since you do this with code already, you should get the term id and replace it in the custom sql query.

$query = "
SELECT $wpdb->posts.* FROM $wpdb->posts
LEFT JOIN $wpdb->term_relationships
ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id)
LEFT JOIN $wpdb->term_taxonomy
ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
WHERE $wpdb->posts.post_type = 'post'
AND $wpdb->posts.post_status = 'publish'
AND $wpdb->term_taxonomy.taxonomy = 'artist_tag'
AND $wpdb->term_taxonomy.term_id = 1
AND NOT EXISTS (SELECT * FROM $wpdb->posts AS post2
LEFT JOIN $wpdb->term_relationships AS termrelation2
ON (post2.ID = termrelation2.object_id)
LEFT JOIN $wpdb->term_taxonomy AS termtax2
ON (termrelation2.term_taxonomy_id = termtax2.term_taxonomy_id)
WHERE post2.ID = $wpdb->posts.ID
AND termtax2.taxonomy = 'artist_tag'
AND termtax2.term_id <> 1)
ORDER BY $wpdb->posts.post_date DESC
LIMIT 5
";
$results = $wpdb->get_results($query);
if ( $results ) {
foreach ( $results as $post ) {
setup_postdata( $post );
// do something here
}
wp_reset_postdata();
}

mackrider comments:

Thanks Hai Bui!