How to order posts by the user_login that corresponds to a meta_value (which is a user id)?
Ok, solved this. I had to use the posts_clausesfilter and the following code: function assigned_to_orderby( $clauses, $wp_query ) { global $wpdb; $clauses[‘join’] .= ” LEFT OUTER JOIN {$wpdb->postmeta} ON {$wpdb->posts}.ID={$wpdb->postmeta}.post_id LEFT OUTER JOIN {$wpdb->users} ON {$wpdb->users}.ID={$wpdb->postmeta}.meta_value “; $clauses[‘where’] .= ” AND ({$wpdb->postmeta}.meta_key = ‘assignee’)”; $clauses[‘groupby’] = “{$wpdb->postmeta}.post_id”; $clauses[‘orderby’] = “GROUP_CONCAT({$wpdb->users}.user_login ORDER BY {$wpdb->users}.user_login ASC) “; … Read more