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<appendix id="features">

<title>SQL Conformance</title>

<para>

The formal name of the SQL standard is ISO/IEC 9075 <quote>Database

Language SQL</quote>. A revised version of the standard is released

from time to time; the most recent full update appearing in 2003,

with a partial update appearing in 2006. The 2003 version is

referred to as ISO/IEC 9075:2003, or simply as SQL:2003. The

versions prior to that were SQL:1999 and SQL-92. Each version

from time to time; the most recent update appearing in 2008.

The 2008 version is referred to as ISO/IEC 9075:2008, or simply as SQL:2008.

The versions prior to that were SQL:2003, SQL:1999, and SQL-92. Each version

replaces the previous one, so claims of conformance to earlier

versions have no official merit.

<productname>PostgreSQL</productname> development aims for

</para>

<para>

The <acronym>SQL:2003</acronym> standard is also split into a number

The <acronym>SQL:2008</acronym> and <acronym>SQL:2003</acronym>

standard versions are also split into a number

of parts. Each is known by a shorthand name. Note that these parts

are not consecutively numbered.

</para>

<para>

PostgreSQL supports most of the major features of SQL:2003. Out of

164 mandatory features required for full Core conformance,

PostgreSQL conforms to at least150. In addition, there is a long

PostgreSQL supports most of the major features of SQL:2008. Out of

179 mandatory features required for full Core conformance,

PostgreSQL conforms to at least160. In addition, there is a long

list of supported optional features. It might be worth noting that at

the time of writing, no current version of any database management

system claims full conformance to Core SQL:2003.

system claims full conformance to Core SQL:2008.

</para>

<para>

In the following two sections, we provide a list of those features

that <productname>PostgreSQL</productname> supports, followed by a

list of the features defined in <acronym>SQL:2003</acronym> which

list of the features defined in <acronym>SQL:2008</acronym> which

are not yet supported in <productname>PostgreSQL</productname>.

Both of these lists are approximate: There might be minor details that

are nonconforming for a feature that is listed as supported, and

<title>Unsupported Features</title>

<para>

The following features defined in <acronym>SQL:2003</acronym> are not

The following features defined in <acronym>SQL:2008</acronym> are not

implemented in this release of

<productname>PostgreSQL</productname>. In a few cases, equivalent

functionality is available.

my$yesno =$ARGV[0];

$is_supportedeq$yesno ||next;

$feature_name =~s/</&lt;/g;

$feature_name =~s/>/&gt;/g;

$subfeature_name =~s/</&lt;/g;

$subfeature_name =~s/>/&gt;/g;