I have a custom taxonomy and I wish to do a query for all custom posts who has no value assigned for that taxonomy (i.e. uncategorised).
This is what I have so far:
$uncatQuery = new WP_Query( array( 'post_type' => 'course', 'tax_query' => array ( array( 'taxonomy' => 'course_category', 'field' => 'name', 'terms' => '', ) ) ) );
However this does not work.
NOTE: I manage to get it to work by creating a query to get all tax ids and then use a NOT IN operator, but that requires an additional query.