select * from data where sn='221' and pq='hum' order by id desc limit 4
idsntspqvaluesystemts
20702582 221 hum 55.60 1558463235 Tue 21 05 2019 20:27:15
20702571 221 hum 55.80 1558463215 Tue 21 05 2019 20:26:55
20702566 221 hum 55.90 1558463214 Tue 21 05 2019 20:26:54
20702556 221 hum 55.60 1558463195 Tue 21 05 2019 20:26:35

Tue May 21 20:27:24 2019 by walley