Derivative function unnecessarily requires aggregate function

[peekeri]

version: 0.9.4.1
rpm: https://s3.amazonaws.com/influxdb/influxdb_0.9.4.1_amd64.deb
system: amazon linux 3.14.35-28.38.amzn1.x86_64

Running query:

select derivative(count) from "jvm.gc" group by instanceId, name

works fine, while:

select derivative(count) from "jvm.gc" where time > now() - 3600s group by instanceId, name

returns error:

ERR: error parsing query: aggregate function required inside the call to derivative

I don't think the second query should require aggregate function call, because there is no grouping by time. Query just limits the amount of rows returned, but does not change the first query in any other way.

[rkuchan]

@jwilder

[peekeri]

I made a pull request with proposed fix for this. If it seems like the right thing to do, I can also add tests for it.

[HakShak]

See grafana/grafana#2802

[beckettsean]

closing in favor of #4187