select * from data where sn='221' and pq='temp' order by id desc limit 4
idsntspqvaluesystemts
18877181 221 temp 12.50 1553490993 Mon 25 03 2019 06:16:33
18877174 221 temp 12.50 1553490991 Mon 25 03 2019 06:16:31
18877165 221 temp 12.50 1553490985 Mon 25 03 2019 06:16:25
18877151 221 temp 12.50 1553490874 Mon 25 03 2019 06:14:34

Mon Mar 25 06:16:35 2019 by walley