I'm trying to use get_posts() to pull articles that have not been assigned a specific custom field. For example (not working):
$articles = get_posts(array( 'post_parent' => 0, 'post_type' => 'custom-type', 'meta_query' => array( array( 'key' => 'alternate_page', 'value' => array(0, '', null), 'compare' => 'IN' ), ) ));
Basically, I want all 'custom-type' articles that don't have a parent and don't have the 'alternate_page' custom field assigned.
I've read elsewhere about doing two queries, one for all articles that have the custom field, getting and array of their IDs, and using the '__post_not_in' parameter, but this seems tedious.
Is it possible to do in one query like above? Thanks.