I'm using a custom field query (or trying to) :
$args = array( 'post_type' => 'pf_cookbook', 'meta_query' => array( 'key' => 'pf_cookbook_recipes', 'value' => '5', 'compare' => 'NOT IN', 'type' => 'NUMERIC' ) );
However, the meta value to be compared is an array. The idea here is I am querying the DB to get the cookbooks which don't contain a certain recipe. The Recipes & Cookbooks are Custom Post Types. The Cookbooks have a meta key 'pf_cookbook_recipes' which I am storing an array of recipe IDs.
Maybe I am missing something?