CODEWITHSUNDEEP
sqlinfluxdbcontinuous
shicky
shicky

Reputation: 1249

Continuous query to calculate difference in InfluxDB

Most common use for continuous query is to calculate average etc.

CREATE CONTINUOUS QUERY minnie ON world BEGIN SELECT min(mouse) INTO min_mouse FROM zoo GROUP BY time(30m) END

I have data points with increment values I am attempting to calculate the difference in value in every interval.

INSERT mydb value=4  1470101034546846145
INSERT mydb value=8  1470101042290558132
INSERT mydb value=10 1470101043594271416

I want to get 10 - 4 = 6 for example.

Is there a way to achieve this using continuous query?

Upvotes: 2

Views: 3102

Answers (2)

Jason
Jason

Reputation: 2597

Your options are

  • DIFFERENCE() for sequential differences. In you example, DIFFERENCE(mouse) would give 8-4, 10-8, etc. This might be useful for you, but doesn't fit your description.
  • SPREAD(): seems to be what you're looking for, which is shorthand for MAX(mouse) - MIN(mouse) on the interval. So something like: SELECT SPREAD(mouse) AS "mouse_range" INTO mouse_calcs FROM zoo GROUP BY time(30m), where mouse_range and mouse_calcs are names I picked with no special meaning.

Upvotes: 1

corentingi
corentingi

Reputation: 305

Try using the new DIFFERENCE() function in your query: https://docs.influxdata.com/influxdb/v0.13/query_language/functions/#difference

SELECT DIFFERENCE(<function>(<field_key>)) FROM <measurement_name> WHERE <stuff> GROUP BY time(<time_interval>)

This is available since v0.13 I think.

Upvotes: 1

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