[[mapping-date-format]]
== Date Format

In JSON documents, dates are represented as strings. Elasticsearch uses a set
of pre-configured format to recognize and convert those, but you can change the
defaults by specifying the `format` option when defining a `date` type, or by
specifying `dynamic_date_formats` in the `root object` mapping (which will
be used unless explicitly overridden by a `date` type). There are built in
formats supported, as well as complete custom one.

The parsing of dates uses http://www.joda.org/joda-time/[Joda]. The
default date parsing used if no format is specified is
http://www.joda.org/joda-time/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateOptionalTimeParser--[ISODateTimeFormat.dateOptionalTimeParser].

An extension to the format allow to define several formats using `||`
separator. This allows to define less strict formats that can be used,
for example, the `yyyy/MM/dd HH:mm:ss||yyyy/MM/dd` format will parse
both `yyyy/MM/dd HH:mm:ss` and `yyyy/MM/dd`. The first format will also
act as the one that converts back from milliseconds to a string
representation.

[float]
[[date-math]]
=== Date Math

The `date` type supports using date math expression when using it in a
query/filter (mainly makes sense in `range` query/filter).

The expression starts with an "anchor" date, which can be either `now`
or a date string (in the applicable format) ending with `||`. It can
then follow by a math expression, supporting `+`, `-` and `/`
(rounding). The units supported are `y` (year), `M` (month), `w` (week),
`d` (day), `h` (hour), `m` (minute), and `s` (second).

Here are some samples: `now+1h`, `now+1h+1m`, `now+1h/d`,
`2012-01-01||+1M/d`.

When doing `range` type searches with rounding, the value parsed
depends on whether the end of the range is inclusive or exclusive, and
whether the beginning or end of the range.  Rounding up moves to the
last millisecond of the rounding scope, and rounding down to the
first millisecond of the rounding scope. The semantics work as follows:
* `gt` - round up, and use > that value (`2014-11-18||/M` becomes `2014-11-30T23:59:59.999`, ie excluding the entire month)
* `gte` - round D down, and use >= that value (`2014-11-18||/M` becomes `2014-11-01`, ie including the entire month)
* `lt` - round D down, and use < that value (`2014-11-18||/M` becomes `2014-11-01`, ie excluding the entire month)
* `lte` - round D up, and use <= that value(`2014-11-18||/M` becomes `2014-11-30T23:59:59.999`, ie including the entire month)

[float]
[[built-in]]
=== Built In Formats

The following tables lists all the defaults ISO formats supported:

[cols="<,<",options="header",]
|=======================================================================
|Name |Description
|`basic_date`|A basic formatter for a full date as four digit year, two
digit month of year, and two digit day of month (yyyyMMdd).

|`basic_date_time`|A basic formatter that combines a basic date and time,
separated by a 'T' (yyyyMMdd'T'HHmmss.SSSZ).

|`basic_date_time_no_millis`|A basic formatter that combines a basic date
and time without millis, separated by a 'T' (yyyyMMdd'T'HHmmssZ).

|`basic_ordinal_date`|A formatter for a full ordinal date, using a four
digit year and three digit dayOfYear (yyyyDDD).

|`basic_ordinal_date_time`|A formatter for a full ordinal date and time,
using a four digit year and three digit dayOfYear
(yyyyDDD'T'HHmmss.SSSZ).

|`basic_ordinal_date_time_no_millis`|A formatter for a full ordinal date
and time without millis, using a four digit year and three digit
dayOfYear (yyyyDDD'T'HHmmssZ).

|`basic_time`|A basic formatter for a two digit hour of day, two digit
minute of hour, two digit second of minute, three digit millis, and time
zone offset (HHmmss.SSSZ).

|`basic_time_no_millis`|A basic formatter for a two digit hour of day,
two digit minute of hour, two digit second of minute, and time zone
offset (HHmmssZ).

|`basic_t_time`|A basic formatter for a two digit hour of day, two digit
minute of hour, two digit second of minute, three digit millis, and time
zone off set prefixed by 'T' ('T'HHmmss.SSSZ).

|`basic_t_time_no_millis`|A basic formatter for a two digit hour of day,
two digit minute of hour, two digit second of minute, and time zone
offset prefixed by 'T' ('T'HHmmssZ).

|`basic_week_date`|A basic formatter for a full date as four digit
weekyear, two digit week of weekyear, and one digit day of week
(xxxx'W'wwe).

|`basic_week_date_time`|A basic formatter that combines a basic weekyear
date and time, separated by a 'T' (xxxx'W'wwe'T'HHmmss.SSSZ).

|`basic_week_date_time_no_millis`|A basic formatter that combines a basic
weekyear date and time without millis, separated by a 'T'
(xxxx'W'wwe'T'HHmmssZ).

|`date`|A formatter for a full date as four digit year, two digit month
of year, and two digit day of month (yyyy-MM-dd).

|`date_hour`|A formatter that combines a full date and two digit hour of
day.

|`date_hour_minute`|A formatter that combines a full date, two digit hour
of day, and two digit minute of hour.

|`date_hour_minute_second`|A formatter that combines a full date, two
digit hour of day, two digit minute of hour, and two digit second of
minute.

|`date_hour_minute_second_fraction`|A formatter that combines a full
date, two digit hour of day, two digit minute of hour, two digit second
of minute, and three digit fraction of second
(yyyy-MM-dd'T'HH:mm:ss.SSS).

|`date_hour_minute_second_millis`|A formatter that combines a full date,
two digit hour of day, two digit minute of hour, two digit second of
minute, and three digit fraction of second (yyyy-MM-dd'T'HH:mm:ss.SSS).

|`date_optional_time`|a generic ISO datetime parser where the date is
mandatory and the time is optional.

|`date_time`|A formatter that combines a full date and time, separated by
a 'T' (yyyy-MM-dd'T'HH:mm:ss.SSSZZ).

|`date_time_no_millis`|A formatter that combines a full date and time
without millis, separated by a 'T' (yyyy-MM-dd'T'HH:mm:ssZZ).

|`hour`|A formatter for a two digit hour of day.

|`hour_minute`|A formatter for a two digit hour of day and two digit
minute of hour.

|`hour_minute_second`|A formatter for a two digit hour of day, two digit
minute of hour, and two digit second of minute.

|`hour_minute_second_fraction`|A formatter for a two digit hour of day,
two digit minute of hour, two digit second of minute, and three digit
fraction of second (HH:mm:ss.SSS).

|`hour_minute_second_millis`|A formatter for a two digit hour of day, two
digit minute of hour, two digit second of minute, and three digit
fraction of second (HH:mm:ss.SSS).

|`ordinal_date`|A formatter for a full ordinal date, using a four digit
year and three digit dayOfYear (yyyy-DDD).

|`ordinal_date_time`|A formatter for a full ordinal date and time, using
a four digit year and three digit dayOfYear (yyyy-DDD'T'HH:mm:ss.SSSZZ).

|`ordinal_date_time_no_millis`|A formatter for a full ordinal date and
time without millis, using a four digit year and three digit dayOfYear
(yyyy-DDD'T'HH:mm:ssZZ).

|`time`|A formatter for a two digit hour of day, two digit minute of
hour, two digit second of minute, three digit fraction of second, and
time zone offset (HH:mm:ss.SSSZZ).

|`time_no_millis`|A formatter for a two digit hour of day, two digit
minute of hour, two digit second of minute, and time zone offset
(HH:mm:ssZZ).

|`t_time`|A formatter for a two digit hour of day, two digit minute of
hour, two digit second of minute, three digit fraction of second, and
time zone offset prefixed by 'T' ('T'HH:mm:ss.SSSZZ).

|`t_time_no_millis`|A formatter for a two digit hour of day, two digit
minute of hour, two digit second of minute, and time zone offset
prefixed by 'T' ('T'HH:mm:ssZZ).

|`week_date`|A formatter for a full date as four digit weekyear, two
digit week of weekyear, and one digit day of week (xxxx-'W'ww-e).

|`week_date_time`|A formatter that combines a full weekyear date and
time, separated by a 'T' (xxxx-'W'ww-e'T'HH:mm:ss.SSSZZ).

|`weekDateTimeNoMillis`|A formatter that combines a full weekyear date
and time without millis, separated by a 'T' (xxxx-'W'ww-e'T'HH:mm:ssZZ).

|`week_year`|A formatter for a four digit weekyear.

|`weekyearWeek`|A formatter for a four digit weekyear and two digit week
of weekyear.

|`weekyearWeekDay`|A formatter for a four digit weekyear, two digit week
of weekyear, and one digit day of week.

|`year`|A formatter for a four digit year.

|`year_month`|A formatter for a four digit year and two digit month of
year.

|`year_month_day`|A formatter for a four digit year, two digit month of
year, and two digit day of month.

|`epoch_second`|A formatter for the number of seconds since the epoch.
Note, that this timestamp allows a max length of 10 chars, so dates
older than 1653 and 2286 are not supported. You should use a different
date formatter in that case.

|`epoch_millis`|A formatter for the number of milliseconds since the epoch.
Note, that this timestamp allows a max length of 13 chars, so dates
older than 1653 and 2286 are not supported. You should use a different
date formatter in that case.
|=======================================================================

[float]
[[custom]]
=== Custom Format

Allows for a completely customizable date format explained
http://joda-time.sourceforge.net/api-release/org/joda/time/format/DateTimeFormat.html[here].