elasticsearch/docs/reference/esql/functions/percentile.asciidoc

[discrete]
[[esql-agg-percentile]]
=== `PERCENTILE`

*Syntax*

[source,esql]
----
PERCENTILE(expression, percentile)
----

*Parameters*

`expression`::
Expression from which to return a percentile.

`percentile`::
A constant numeric expression.

*Description*

Returns the value at which a certain percentage of observed values occur. For
example, the 95th percentile is the value which is greater than 95% of the
observed values and the 50th percentile is the <<esql-agg-median>>.

*Example*

[source.merge.styled,esql]
----
include::{esql-specs}/stats_percentile.csv-spec[tag=percentile]
----
[%header.monospaced.styled,format=dsv,separator=|]
|===
include::{esql-specs}/stats_percentile.csv-spec[tag=percentile-result]
|===

The expression can use inline functions. For example, to calculate a percentile
of the maximum values of a multivalued column, first use `MV_MAX` to get the
maximum value per row, and use the result with the `PERCENTILE` function:

[source.merge.styled,esql]
----
include::{esql-specs}/stats_percentile.csv-spec[tag=docsStatsPercentileNestedExpression]
----
[%header.monospaced.styled,format=dsv,separator=|]
|===
include::{esql-specs}/stats_percentile.csv-spec[tag=docsStatsPercentileNestedExpression-result]
|===

[discrete]
[[esql-agg-percentile-approximate]]
==== `PERCENTILE` is (usually) approximate

include::../../aggregations/metrics/percentile-aggregation.asciidoc[tag=approximate]

[WARNING]
====
`PERCENTILE` is also {wikipedia}/Nondeterministic_algorithm[non-deterministic].
This means you can get slightly different results using the same data.
====