<?php

/**
 * Get Terms used by Post Type
 * Fetches only terms actually used by posts of a specified post type
 *
 * @param 	string  $taxonomy		the taxonomy to look for terms
 * @param 	string	$post_type  the post type to match the taxonomy terms found
 *
 * @return	array   the query result (an array of taxonomy terms as objects)
 */
function get_terms_by_post_type( $taxonomy, $post_type ) {

	global $wpdb;
	$query = $wpdb->get_results(
		"SELECT t.*, COUNT(*) from $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id INNER JOIN $wpdb->term_relationships AS r ON r.term_taxonomy_id = tt.term_taxonomy_id INNER JOIN $wpdb->posts AS p ON p.ID = r.object_id WHERE p.post_type IN('" . $post_type . "') AND tt.taxonomy IN('" . $taxonomy . "') GROUP BY t.term_id"
	);

	return $query;
}