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<chapter id="datatype">

<replaceable>p</replaceable> should be between 0 and 6, and

defaults to the precision of the input literal.

</para>

<para>

Alternatively, <type>interval</type> values can be written as

ISO 8601 time intervals, using the "Format with time-unit designators".

This format always starts with the character <literal>'P'</>, followed

by a string of values followed by single character time-unit designators.

A <literal>'T'</> separates the date and time parts of the interval.

</para>

<para>

Format: PnYnMnDTnHnMnS

</para>

<para>

In this format, <literal>'n'</> gets replaced by a number, and

<literal>Y</> represents years,

<literal>M</> (in the date part) months,

<literal>D</> months,

<literal>H</> hours,

<literal>M</> (in the time part) minutes,

and <literal>S</> seconds.

</para>

<table id="interval-example-table">

<title>Interval Example</title>

<tgroup cols="2">

<thead>

<row>

<entry>Traditional</entry>

<entry>ISO-8601 time-interval</entry>

</row>

</thead>

<tbody>

<row>

<entry>1 month</entry>

<entry>P1M</entry>

</row>

<row>

<entry>1 hour 30 minutes</entry>

<entry>PT1H30M</entry>

</row>

<row>

<entry>2 years 10 months 15 days 10 hours 30 minutes 20 seconds</entry>

<entry>P2Y10M15DT10H30M20S</entry>

</row>

</tbody>

</tgroup>

</table>

</sect3>

<sect3>

<entry>regional style</entry>

<entry>17.12.1997 07:37:16.00 PST</entry>

</row>

<row>

<entry>ISO8601basic</entry>

<entry>ISO 8601 basic format</entry>

<entry>19971217T073716-08</entry>

</row>

</tbody>

</tgroup>

</table>

</programlisting>

</para>

<para>

If the <varname>datestyle</> is set to iso8601basic, the interval

output is a ISO-8601 time interval with time-unit designator (like P1Y6M or PT23H59M59S).

</para>

<para>

The date/time styles can be selected by the user using the

<command>SET datestyle</command> command, the

if (strcasecmp(tok,"ISO8601BASIC")==0)

{

newDateStyle=USE_ISO8601BASIC_DATES;

scnt++;

}

elseif (strcasecmp(tok,"ISO")==0)

if (strcasecmp(tok,"ISO")==0)

{

newDateStyle=USE_ISO_DATES;

scnt++;

caseUSE_ISO_DATES:

strcpy(result,"ISO");

break;

caseUSE_ISO8601BASIC_DATES:

strcpy(result,"ISO8601BASIC");

break;

caseUSE_SQL_DATES:

strcpy(result,"SQL");

break;