Wordpress database cleanup queries

-- from http://greatest-blog.com/

-- Delete revisions
DELETE a,b,c
FROM wp_posts a
LEFT JOIN wp_term_relationships b ON (a.ID = b.object_id)
LEFT JOIN wp_postmeta c ON (a.ID = c.post_id)
WHERE a.post_type = 'revision';

-- Delete postmeta on inexistant posts
DELETE pm
FROM wp_postmeta pm
LEFT JOIN wp_posts wp ON wp.ID = pm.post_id
WHERE wp.ID IS NULL;;

-- Delete orphaned wp_term_relationships
DELETE tr
FROM wp_term_relationships tr
INNER JOIN wp_term_taxonomy tt ON (tr.term_taxonomy_id = tt.term_taxonomy_id)
WHERE tt.taxonomy != 'link_category'
AND tr.object_id NOT IN (SELECT ID FROM wp_posts);

-- Delete unused tags
DELETE a,c
FROM wp_terms AS a
LEFT JOIN wp_term_taxonomy AS c ON a.term_id = c.term_id
LEFT JOIN wp_term_relationships AS b ON b.term_taxonomy_id = c.term_taxonomy_id
WHERE (
    c.taxonomy = 'post_tag' AND
    c.COUNT = 0
);

-- Delete orphaned commentmeta
DELETE
FROM wp_commentmeta
WHERE comment_id NOT IN (SELECT comment_id FROM wp_comments);