Hack the WordPress Loop to Exclude Subcategories
The WordPress loop by default includes child categories of each parent category. Most of the time this is not a problem. However, if you’re trying to customize the loop to include only parent categories, then you’ll need a little bit of help.
I found this function over at WPEngineer.com. Simply drop it into your theme’s functions.php file and your loop will automatically exclude subcategories:
if ( !function_exists('fb_filter_child_cats') ) { function fb_filter_child_cats( $cats ) { global $wp_query, $wpdb; if ( is_category() ) { // get children ID's if ( $excludes = get_categories( "child_of=" . $wp_query->get('cat') ) ) { // set array with ID's foreach ( $excludes as $key => $value ) { $exclude[] = $value->cat_ID; } } // remove child cats if ( isset($exclude) && is_array($exclude) ) { $cats .= " AND " . $wpdb->prefix . "term_relationships.term_taxonomy_id NOT IN (" . implode(",", $exclude) . ") "; } } return $cats; } if ( !is_admin() ) { add_filter( 'posts_where', 'fb_filter_child_cats' ); } }
Tested on WP 3.1.