select * from data where sn='ds1' order by id desc limit 4
idsntspqvaluesystemts
20703435 ds1 temp 15.13 1558464696 Tue 21 05 2019 20:51:36
20703419 ds1 temp 15.13 1558464674 Tue 21 05 2019 20:51:14
20703403 ds1 temp 15.13 1558464652 Tue 21 05 2019 20:50:52
20703395 ds1 temp 15.13 1558464630 Tue 21 05 2019 20:50:30

Tue May 21 20:51:42 2019 by walley