select * from data where sn='221' and pq='hum' order by id desc limit 4
idsntspqvaluesystemts
18877152 221 hum 52.90 1553490874 Mon 25 03 2019 06:14:34
18877145 221 hum 52.90 1553490853 Mon 25 03 2019 06:14:13
18877139 221 hum 52.90 1553490852 Mon 25 03 2019 06:14:12
18877128 221 hum 52.90 1553490833 Mon 25 03 2019 06:13:53

Mon Mar 25 06:15:07 2019 by walley