elasticsearch/docs/reference/esql/functions/examples/to_datetime.asciidoc

// This is generated by ESQL's AbstractFunctionTestCase. Do no edit it. See ../README.md for how to regenerate it.

*Examples*

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

Note that in this example, the last value in the source multi-valued field has not been converted.
The reason being that if the date format is not respected, the conversion will result in a *null* value.
When this happens a _Warning_ header is added to the response.
The header will provide information on the source of the failure:

`"Line 1:112: evaluation of [TO_DATETIME(string)] failed, treating result as null. "Only first 20 failures recorded."`

A following header will contain the failure reason and the offending value:

`"java.lang.IllegalArgumentException: failed to parse date field [1964-06-02 00:00:00]
with format [yyyy-MM-dd'T'HH:mm:ss.SSS'Z']"`


If the input parameter is of a numeric type,
its value will be interpreted as milliseconds since the {wikipedia}/Unix_time[Unix epoch]. For example:
[source.merge.styled,esql]
----
include::{esql-specs}/date.csv-spec[tag=to_datetime-int]
----
[%header.monospaced.styled,format=dsv,separator=|]
|===
include::{esql-specs}/date.csv-spec[tag=to_datetime-int-result]
|===