Converts an input value to a date value.

The input can be a single- or multi-valued field or an expression. The input type must be of a string or numeric type.

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). For example:

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)

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)

Alias: TO_DT