---
title: ES|QL TO_DATETIME function
description: 
url: https://www.elastic.co/docs/reference/query-languages/esql/functions-operators/type-conversion-functions/to_datetime
products:
  - Elasticsearch
---

# ES|QL TO_DATETIME function
## Syntax

![Embedded](https://www.elastic.co/docs/reference/query-languages/esql/images/generated/x-pack-esql/functions/to_datetime.svg)


## Parameters

<definitions>
  <definition term="field">
    Input value. The input can be a single- or multi-valued column or an expression.
  </definition>
</definitions>


## Description

Converts an input value to a date value. A string will only be successfully converted if it’s respecting the format `yyyy-MM-dd'T'HH:mm:ss.SSS'Z'`. To convert dates in other formats, use [`DATE_PARSE`](https://www.elastic.co/docs/reference/query-languages/esql/functions-operators/date-time-functions/date_parse).
<note>
  Note that when converting from nanosecond resolution to millisecond resolution with this function, the nanosecond date is truncated, not rounded.
</note>


## Supported types


| field         | result |
|---------------|--------|
| date          | date   |
| date_nanos    | date   |
| double        | date   |
| integer       | date   |
| keyword       | date   |
| long          | date   |
| text          | date   |
| unsigned_long | date   |


## Examples

```esql
ROW string = ["1953-09-02T00:00:00.000Z", "1964-06-02T00:00:00.000Z", "1964-06-02 00:00:00"]
| EVAL datetime = TO_DATETIME(string)
```


| string:keyword                                                                  | datetime:date                                        |
|---------------------------------------------------------------------------------|------------------------------------------------------|
| ["1953-09-02T00:00:00.000Z", "1964-06-02T00:00:00.000Z", "1964-06-02 00:00:00"] | [1953-09-02T00:00:00.000Z, 1964-06-02T00:00:00.000Z] |

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 [Unix epoch](https://en.wikipedia.org/wiki/Unix_time). For example:
```esql
ROW int = [0, 1]
| EVAL dt = TO_DATETIME(int)
```


| int:integer | dt:date                                              |
|-------------|------------------------------------------------------|
| [0, 1]      | [1970-01-01T00:00:00.000Z, 1970-01-01T00:00:00.001Z] |