select * from data where sn='max1' and pq='volt' order by id desc limit 4
idsntspqvaluesystemts
6107346 max1 volt 6.519 1505613499 Sun 17 09 2017 03:58:19
6107334 max1 volt 6.567 1505613400 Sun 17 09 2017 03:56:40
6107296 max1 volt 6.812 1505613359 Sun 17 09 2017 03:55:59
6107292 max1 volt 6.909 1505613300 Sun 17 09 2017 03:55:00

Sun Jul 21 04:04:38 2019 by walley