Finds all overlapping WordPress posts between two categories

wordpress_find_all_overlapping_posts_in_categories.sql

SELECT 
    posts.ID, posts.post_title
FROM
    wp.hpu_posts AS posts
        INNER JOIN
    wp.term_relationships AS rel ON posts.ID = rel.object_id
        INNER JOIN
    wp.term_taxonomy AS tax ON tax.term_taxonomy_id = rel.term_taxonomy_id
WHERE
    tax.term_id = 17
        AND posts.ID IN (SELECT 
            posts.ID
        FROM
            wp.posts AS posts
                INNER JOIN
            wp.term_relationships AS rel ON posts.ID = rel.object_id
                INNER JOIN
            wp.term_taxonomy AS tax ON tax.term_taxonomy_id = rel.term_taxonomy_id
        WHERE
            tax.term_id = 17 AND post_type = 'post')
        AND post_type = 'post'