DELETE ubbt_USERS,
ubbt_USER_DATA,
ubbt_USER_PROFILE,
ubbt_PRIVATE_MESSAGE_USERS,
ubbt_PRIVATE_MESSAGE_TOPICS,
ubbt_PRIVATE_MESSAGE_POSTS
FROM ubbt_USERS as u
LEFT JOIN ubbt_USER_DATA AS ud ON ud.USER_ID = u.USER_ID
LEFT JOIN ubbt_USER_PROFILE AS uprof ON uprof.USER_ID = u.USER_ID
LEFT JOIN ubbt_PRIVATE_MESSAGE_USERS AS upmu ON upmu.USER_ID = u.USER_ID
LEFT JOIN ubbt_PRIVATE_MESSAGE_TOPICS AS upmt ON upmt.TOPIC_ID = upmu.TOPIC_ID
LEFT JOIN ubbt_PRIVATE_MESSAGE_POSTS AS upmp ON upmp.TOPIC_ID = upmu.TOPIC_ID
WHERE USER_RULES_ACCEPTED=0
AND USER_REGISTERED_ON=USER_LAST_VISIT_TIME
AND USER_LAST_IP IS NULL;