A range aggregation that is dedicated for date values. The main difference between this aggregation and the normal <<search-aggregations-bucket-range-aggregation,range>> aggregation is that the `from` and `to` values can be expressed in <<date-math,Date Math>> expressions, and it is also possible to specify a date format by which the `from` and `to` response fields will be returned.
The count of pattern letters determine the format.
Text:: If the number of pattern letters is 4 or more, the full form is used; otherwise a short or abbreviated form is used if available.
Number:: The minimum number of digits. Shorter numbers are zero-padded to this amount.
Year:: Numeric presentation for year and weekyear fields are handled specially. For example, if the count of 'y' is 2, the year will be displayed as the zero-based year of the century, which is two digits.
Month:: 3 or over, use text, otherwise use number.
Zone:: 'Z' outputs offset without a colon, 'ZZ' outputs the offset with a colon, 'ZZZ' or more outputs the zone id.
Zone names:: Time zone names ('z') cannot be parsed.
Any characters in the pattern that are not in the ranges of ['a'..'z'] and ['A'..'Z'] will be treated as quoted text. For instance, characters like ':', '.', ' ', '#' and '?' will appear in the resulting time text even they are not embraced within single quotes.