Useful scripts for my WordPress sites

To reset the tags of my posts in a particular category:

-- 1. Get term_taxonomy_id for category "tweets"
SELECT term_taxonomy_id 
FROM wp_term_taxonomy tt 
JOIN wp_terms t ON t.term_id = tt.term_id 
WHERE t.name = 'tweets' AND tt.taxonomy = 'category';

-- suppose this returns term_taxonomy_id = X

-- 2. Remove all tag relationships for posts in that category
DELETE tr 
FROM wp_term_relationships tr 
JOIN wp_term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id 
WHERE tt.taxonomy = 'post_tag'
AND tr.object_id IN (
    SELECT object_id FROM (
        SELECT object_id FROM wp_term_relationships 
        WHERE term_taxonomy_id = 10
    ) AS temp
);