check multiple taxonomies in WHERE statement of SELECT Query

Didn’t test this much, but try:

<?php
$query="SELECT $wpdb->posts.* FROM $wpdb->posts
INNER JOIN $wpdb->term_relationships ON ($wpdb->posts.ID = $wpdb->term_relationships.object_id)
INNER JOIN $wpdb->term_taxonomy ON ($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id)
WHERE 1=1  AND $wpdb->term_taxonomy.taxonomy IN ('post_tag','art','love','genre')
AND $wpdb->posts.post_type = 'post'
AND ($wpdb->posts.post_status = 'publish')
GROUP BY $wpdb->posts.ID
ORDER BY $wpdb->posts.post_date DESC";
$results=$wpdb->get_results($query);
  foreach ($results as $result) {
echo "<pre>"; print_r($result); echo "</pre>";
}
?>

Excellent. Thank you so much. I can’t wait until this is second nature to me. I just have to keep reading my php books. ??

I just came to the forum to share some code relating to multiple taxonomies and similar posts… here’s what I wrote up this afternoon:

SELECT s.object_id, COUNT(*) AS matches FROM wp_posts x, wp_term_relationships s INNER JOIN (SELECT r.term_taxonomy_id FROM wp_term_relationships r, wp_term_taxonomy t WHERE r.object_id = '$id' AND r.term_taxonomy_id = t.term_taxonomy_id AND (t.taxonomy = 'style' OR t.taxonomy = 'artist' OR t.taxonomy = 'label')) p ON p.term_taxonomy_id = s.term_taxonomy_id WHERE object_id != '$id' AND x.ID = s.object_id AND x.post_status = 'publish' GROUP BY s.object_id HAVING matches > 1 ORDER BY matches DESC, RAND() LIMIT 3

Xerotones code works perfect! How is it possible to get an array with all the tax-terms which are matching the original post’s terms into the result object?

The object foreach related post looks like this:

stdClass Object
(
    [object_id] => 458
    [matches] => 4
)

and I’d like it to look like this:

stdClass Object
(
    [object_id] => 458
    [matches] => 4
	[matching_terms] => Array(
							[0] => 146
							[1] => 155
							[2] => 190
							[3] => 213
						)
)

Can this be done? Thank You for help!