median() function

median() returns the median _value of an input table or all non-null records in the input table with values that fall within the 0.5 quantile (50th percentile).

Function behavior

median() acts as an aggregate or selector transformation depending on the specified method.

  • Aggregate: When using the estimate_tdigest or exact_mean methods, median() acts as an aggregate transformation and outputs the average of non-null records with values that fall within the 0.5 quantile (50th percentile).
  • Selector: When using the exact_selector method, meidan() acts as a selector selector transformation and outputs the non-null record with the value that represents the 0.5 quantile (50th percentile).
Function type signature
(<-tables: stream[A], ?column: string, ?compression: float, ?method: string) => stream[A] where A: Record

For more information, see Function type signatures.



Column to use to compute the median. Default is _value.


Computation method. Default is estimate_tdigest.

Available methods:

  • estimate_tdigest: Aggregate method that uses a t-digest data structure to compute an accurate median estimate on large data sources.
  • exact_mean: Aggregate method that takes the average of the two points closest to the median value.
  • exact_selector: Selector method that returns the row with the value for which at least 50% of points are less than.


Number of centroids to use when compressing the dataset. Default is 0.0.

A larger number produces a more accurate result at the cost of increased memory requirements.


Input data. Default is piped-forward data (<-).


Use median as an aggregate transformation

import "sampledata"

    |> median()

View example input and output

Use median as a selector transformation

import "sampledata"

    |> median(method: "exact_selector")

View example input and output

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The future of Flux

Flux is going into maintenance mode. You can continue using it as you currently are without any changes to your code.

Flux is going into maintenance mode and will not be supported in InfluxDB 3.0. This was a decision based on the broad demand for SQL and the continued growth and adoption of InfluxQL. We are continuing to support Flux for users in 1.x and 2.x so you can continue using it with no changes to your code. If you are interested in transitioning to InfluxDB 3.0 and want to future-proof your code, we suggest using InfluxQL.

For information about the future of Flux, see the following: