Example:
select created_at, date, value from measurements order by created_at desc limit 10;
->
2016-03-16 14:00:33.262361 | 2016-03-16 12:00:00 | [{"signal_strength":-81,"std":1},{"signal_strength":-57,"std":6},{"signal_strength":-54,"std":6},{"signal_strength":-38,"std":5}]