select * from data where sn='221' order by id desc limit 4
idsntspqvaluesystemts
39740405 221 temp 19.30 1594700596 Tue 14 07 2020 06:23:16
39740404 221 hum 31.60 1594700596 Tue 14 07 2020 06:23:16
39740400 221 hum 31.60 1594700594 Tue 14 07 2020 06:23:14
39740399 221 temp 19.30 1594700594 Tue 14 07 2020 06:23:14

Tue Jul 14 06:23:27 2020 by walley