approx_percentile()

Estimate the value at a given percentile from a tdigest

Since 1.0.0

Estimate the approximate value at a percentile from a tdigest aggregate.

Samples

Estimate the value at the first percentile, given a sample containing the numbers from 0 to 100.

SELECT
  approx_percentile(0.01, tdigest(data))
FROM generate_series(0, 100) data;

approx_percentile
-------------------
            0.999

Arguments

The syntax is:

approx_percentile(
  percentile DOUBLE PRECISION,
  tdigest  TDigest
) RETURNS DOUBLE PRECISION

Name	Type	Default	Required	Description
percentile	DOUBLE PRECISION	-	✔	The percentile to compute. Must be within the range [0.0, 1.0]
tdigest	TDigest	-	✔	The tdigest aggregate

Returns

Column	Type	Description
approx_percentile	DOUBLE PRECISION	The estimated value at the requested percentile.