select * from data where sn='221' order by id desc limit 4
idsntspqvaluesystemts
27168270 221 temp 17.80 1571485046 Sat 19 10 2019 13:37:26
27168269 221 hum 44.50 1571485046 Sat 19 10 2019 13:37:26
27168259 221 hum 45.10 1571485026 Sat 19 10 2019 13:37:06
27168258 221 temp 17.80 1571485026 Sat 19 10 2019 13:37:06

Mon Oct 21 05:21:19 2019 by walley