ES|QL TO_DATETIME function
field-
Input value. The input can be a single- or multi-valued column or an expression.
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.
Note that when converting from nanosecond resolution to millisecond resolution with this function, the nanosecond date is truncated, not rounded.
| field | result |
|---|---|
| date | date |
| date_nanos | date |
| double | date |
| integer | date |
| keyword | date |
| long | date |
| text | date |
| unsigned_long | date |
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. For example:
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] |