Get any WordPress post without any tags

gistfile1.php

<?php
global $wpdb;

$entries = $wpdb->get_results( $wpdb->prepare( "
	SELECT
		p.ID,
		t.term_id
	FROM
		" . $wpdb->posts . " p
	LEFT JOIN
		(
			SELECT
				term_rel.object_id,
				term_rel.term_taxonomy_id,
				t.taxonomy,
				t.term_id
			FROM
				" . $wpdb->term_relationships . " term_rel
			JOIN
				" . $wpdb->term_taxonomy . " t
					ON ( t.term_taxonomy_id = term_rel.term_taxonomy_id )
			WHERE
				t.taxonomy = %s
			GROUP BY
				term_rel.object_id
		) t
		ON ( t.object_id = p.ID )
	WHERE
		t.term_id IS NULL
	AND
		p.post_type = %s
", 'post_tag', 'post' ) );