% This is generated by ESQL's AbstractFunctionTestCase. Do not edit it. See ../README.md for how to regenerate it.

**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] |