If you are using InfluxDB 0.8 dont use FIRST() or LAST() if you have not GROUP BY because its very slow 🙁
So if you want to get the these Values you shoud use:
First Value:
SELECT * FROM <SERIES> GROUP BY * ORDER BY ASC LIMIT 1
Last Value:
SELECT * FROM <SERIES> GROUP BY * ORDER BY DESC LIMIT 1
Don’t delete the GROUP BY * because then it could be possible that you get unexpected values then.