SELECT placeid, placename FROM place WHERE userid = (SELECT id FROM
user WHERE username = 'username' AND password ='password') AND
placename = 'placename'

SELECT boxid, boxname FROM box WHERE placeid = 'id'

DELETE FROM item WHERE boxid = 'boxid'

DELETE FROM box WHERE id = 'boxid'

DELETE FROM item WHERE placeid = 'placeid' AND boxid = 0

DELETE FROM place WHERE id = placeid