bludnic

/* SELECT test */
SELECT ID, reg_replace(post_content, '<aside class="mashsb-container(.*)">((.|\n)*)<\/aside>', '', TRUE, 2, 0) as content
FROM wp_posts
WHERE post_content REGEXP('<aside class="mashsb-container(.*)">((.|\n)*)<\/aside>')
LIMIT 1

/* Update */
UPDATE wp_posts
SET post_content = REGEXP_REPLACE('post_content', '<aside class="mashsb-container(.*)">((.|\n)*)<\/aside>', '')
WHERE ID = 469