doc: Update SQL features/conformance information to SQL:2023

Optional subfeatures have been changed to top-level features, so there
is a bit of a churn in the list for that.

Some existing functions have been added to the standard, so they are
moved from the "other" to the "standard" lists in their sections.

Discussion: https://www.postgresql.org/message-id/flat/[email protected]

3 files changed, 181 insertions, 183 deletions

diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index f6b867f344..8d32a8c9c5 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1242,8 +1242,7 @@ SELECT '52093.89'::money::numeric::float8;
     than zero and cannot exceed 10485760.
     <type>character</type> without length specifier is equivalent to
     <type>character(1)</type>. If <type>character varying</type> is used
-    without length specifier, the type accepts strings of any size. The
-    latter behavior is a <productname>PostgreSQL</productname> extension.
+    without length specifier, the type accepts strings of any size.
    </para>
 
    <para>
diff --git a/doc/src/sgml/features.sgml b/doc/src/sgml/features.sgml
index b98056214f..575afa3476 100644
--- a/doc/src/sgml/features.sgml
+++ b/doc/src/sgml/features.sgml
@@ -14,9 +14,9 @@
  <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 update appearing in 2016.
-  The 2016 version is referred to as ISO/IEC 9075:2016, or simply as SQL:2016.
-  The versions prior to that were SQL:2011, SQL:2008, SQL:2006, SQL:2003,
+  from time to time; the most recent update appearing in 2023.
+  The 2023 version is referred to as ISO/IEC 9075:2023, or simply as SQL:2023.
+  The versions prior to that were SQL:2016, SQL:2011, SQL:2008, SQL:2006, SQL:2003,
   SQL:1999, and SQL-92.  Each version
   replaces the previous one, so claims of conformance to earlier
   versions have no official merit.
@@ -62,6 +62,7 @@
    <listitem><para>ISO/IEC 9075-13 Routines and Types using the Java Language (SQL/JRT)</para><indexterm><primary>SQL/JRT</primary></indexterm></listitem>
    <listitem><para>ISO/IEC 9075-14 XML-related specifications (SQL/XML)</para><indexterm><primary>SQL/XML</primary></indexterm></listitem>
    <listitem><para>ISO/IEC 9075-15 Multi-dimensional arrays (SQL/MDA)</para><indexterm><primary>SQL/MDA</primary></indexterm></listitem>
+   <listitem><para>ISO/IEC 9075-16 Property Graph Queries (SQL/PGQ)</para><indexterm><primary>SQL/PGQ</primary></indexterm></listitem>
   </itemizedlist>
 
   Note that some part numbers are not (or no longer) used.
@@ -72,23 +73,23 @@
   11, and 14.  Part 3 is covered by the ODBC driver, and part 13 is
   covered by the PL/Java plug-in, but exact conformance is currently
   not being verified for these components.  There are currently no
-  implementations of parts 4, 10, and 15
+  implementations of parts 4, 10, 15, and 16
   for <productname>PostgreSQL</productname>.
  </para>
 
  <para>
-  PostgreSQL supports most of the major features of SQL:2016.  Out of
+  PostgreSQL supports most of the major features of SQL:2023.  Out of
   177 mandatory features required for full Core conformance,
   PostgreSQL conforms to at least 170.  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:2016.
+  system claims full conformance to Core SQL:2023.
  </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:2016</acronym> which
+  list of the features defined in <acronym>SQL:2023</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
@@ -135,7 +136,7 @@
    <title>Unsupported Features</title>
 
    <para>
-    The following features defined in <acronym>SQL:2016</acronym> are not
+    The following features defined in <acronym>SQL:2023</acronym> are not
     implemented in this release of
     <productname>PostgreSQL</productname>. In a few cases, equivalent
     functionality is available.
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 918a492234..dc44a74eb2 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -2455,6 +2455,26 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
+         <primary>btrim</primary>
+        </indexterm>
+        <function>btrim</function> ( <parameter>string</parameter> <type>text</type>
+        <optional>, <parameter>characters</parameter> <type>text</type> </optional> )
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Removes the longest string containing only characters
+        in <parameter>characters</parameter> (a space by default)
+        from the start and end of <parameter>string</parameter>.
+       </para>
+       <para>
+        <literal>btrim('xyxtrimyyx', 'xyz')</literal>
+        <returnvalue>trim</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
          <primary>normalized</primary>
         </indexterm>
         <indexterm>
@@ -2550,6 +2570,49 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
+         <primary>lpad</primary>
+        </indexterm>
+        <function>lpad</function> ( <parameter>string</parameter> <type>text</type>,
+        <parameter>length</parameter> <type>integer</type>
+        <optional>, <parameter>fill</parameter> <type>text</type> </optional> )
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Extends the <parameter>string</parameter> to length
+        <parameter>length</parameter> by prepending the characters
+        <parameter>fill</parameter> (a space by default).  If the
+        <parameter>string</parameter> is already longer than
+        <parameter>length</parameter> then it is truncated (on the right).
+       </para>
+       <para>
+        <literal>lpad('hi', 5, 'xy')</literal>
+        <returnvalue>xyxhi</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>ltrim</primary>
+        </indexterm>
+        <function>ltrim</function> ( <parameter>string</parameter> <type>text</type>
+        <optional>, <parameter>characters</parameter> <type>text</type> </optional> )
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Removes the longest string containing only characters in
+        <parameter>characters</parameter> (a space by default) from the start of
+        <parameter>string</parameter>.
+       </para>
+       <para>
+        <literal>ltrim('zzzytest', 'xyz')</literal>
+        <returnvalue>test</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
          <primary>normalize</primary>
         </indexterm>
         <indexterm>
@@ -2653,6 +2716,49 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
+         <primary>rpad</primary>
+        </indexterm>
+        <function>rpad</function> ( <parameter>string</parameter> <type>text</type>,
+        <parameter>length</parameter> <type>integer</type>
+        <optional>, <parameter>fill</parameter> <type>text</type> </optional> )
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Extends the <parameter>string</parameter> to length
+        <parameter>length</parameter> by appending the characters
+        <parameter>fill</parameter> (a space by default).  If the
+        <parameter>string</parameter> is already longer than
+        <parameter>length</parameter> then it is truncated.
+       </para>
+       <para>
+        <literal>rpad('hi', 5, 'xy')</literal>
+        <returnvalue>hixyx</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>rtrim</primary>
+        </indexterm>
+        <function>rtrim</function> ( <parameter>string</parameter> <type>text</type>
+         <optional>, <parameter>characters</parameter> <type>text</type> </optional> )
+        <returnvalue>text</returnvalue>
+       </para>
+       <para>
+        Removes the longest string containing only characters in
+        <parameter>characters</parameter> (a space by default) from the end of
+        <parameter>string</parameter>.
+       </para>
+       <para>
+        <literal>rtrim('testxxzx', 'xyz')</literal>
+        <returnvalue>test</returnvalue>
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
          <primary>substring</primary>
         </indexterm>
         <function>substring</function> ( <parameter>string</parameter> <type>text</type> <optional> <literal>FROM</literal> <parameter>start</parameter> <type>integer</type> </optional> <optional> <literal>FOR</literal> <parameter>count</parameter> <type>integer</type> </optional> )
@@ -2845,26 +2951,6 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
-         <primary>btrim</primary>
-        </indexterm>
-        <function>btrim</function> ( <parameter>string</parameter> <type>text</type>
-        <optional>, <parameter>characters</parameter> <type>text</type> </optional> )
-        <returnvalue>text</returnvalue>
-       </para>
-       <para>
-        Removes the longest string containing only characters
-        in <parameter>characters</parameter> (a space by default)
-        from the start and end of <parameter>string</parameter>.
-       </para>
-       <para>
-        <literal>btrim('xyxtrimyyx', 'xyz')</literal>
-        <returnvalue>trim</returnvalue>
-       </para></entry>
-      </row>
-
-      <row>
-       <entry role="func_table_entry"><para role="func_signature">
-        <indexterm>
          <primary>chr</primary>
         </indexterm>
         <function>chr</function> ( <type>integer</type> )
@@ -3002,49 +3088,6 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
-         <primary>lpad</primary>
-        </indexterm>
-        <function>lpad</function> ( <parameter>string</parameter> <type>text</type>,
-        <parameter>length</parameter> <type>integer</type>
-        <optional>, <parameter>fill</parameter> <type>text</type> </optional> )
-        <returnvalue>text</returnvalue>
-       </para>
-       <para>
-        Extends the <parameter>string</parameter> to length
-        <parameter>length</parameter> by prepending the characters
-        <parameter>fill</parameter> (a space by default).  If the
-        <parameter>string</parameter> is already longer than
-        <parameter>length</parameter> then it is truncated (on the right).
-       </para>
-       <para>
-        <literal>lpad('hi', 5, 'xy')</literal>
-        <returnvalue>xyxhi</returnvalue>
-       </para></entry>
-      </row>
-
-      <row>
-       <entry role="func_table_entry"><para role="func_signature">
-        <indexterm>
-         <primary>ltrim</primary>
-        </indexterm>
-        <function>ltrim</function> ( <parameter>string</parameter> <type>text</type>
-        <optional>, <parameter>characters</parameter> <type>text</type> </optional> )
-        <returnvalue>text</returnvalue>
-       </para>
-       <para>
-        Removes the longest string containing only characters in
-        <parameter>characters</parameter> (a space by default) from the start of
-        <parameter>string</parameter>.
-       </para>
-       <para>
-        <literal>ltrim('zzzytest', 'xyz')</literal>
-        <returnvalue>test</returnvalue>
-       </para></entry>
-      </row>
-
-      <row>
-       <entry role="func_table_entry"><para role="func_signature">
-        <indexterm>
          <primary>md5</primary>
         </indexterm>
         <function>md5</function> ( <type>text</type> )
@@ -3508,49 +3551,6 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
-         <primary>rpad</primary>
-        </indexterm>
-        <function>rpad</function> ( <parameter>string</parameter> <type>text</type>,
-        <parameter>length</parameter> <type>integer</type>
-        <optional>, <parameter>fill</parameter> <type>text</type> </optional> )
-        <returnvalue>text</returnvalue>
-       </para>
-       <para>
-        Extends the <parameter>string</parameter> to length
-        <parameter>length</parameter> by appending the characters
-        <parameter>fill</parameter> (a space by default).  If the
-        <parameter>string</parameter> is already longer than
-        <parameter>length</parameter> then it is truncated.
-       </para>
-       <para>
-        <literal>rpad('hi', 5, 'xy')</literal>
-        <returnvalue>hixyx</returnvalue>
-       </para></entry>
-      </row>
-
-      <row>
-       <entry role="func_table_entry"><para role="func_signature">
-        <indexterm>
-         <primary>rtrim</primary>
-        </indexterm>
-        <function>rtrim</function> ( <parameter>string</parameter> <type>text</type>
-         <optional>, <parameter>characters</parameter> <type>text</type> </optional> )
-        <returnvalue>text</returnvalue>
-       </para>
-       <para>
-        Removes the longest string containing only characters in
-        <parameter>characters</parameter> (a space by default) from the end of
-        <parameter>string</parameter>.
-       </para>
-       <para>
-        <literal>rtrim('testxxzx', 'xyz')</literal>
-        <returnvalue>test</returnvalue>
-       </para></entry>
-      </row>
-
-      <row>
-       <entry role="func_table_entry"><para role="func_signature">
-        <indexterm>
          <primary>split_part</primary>
         </indexterm>
         <function>split_part</function> ( <parameter>string</parameter> <type>text</type>,
@@ -4141,6 +4141,46 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
+         <primary>btrim</primary>
+        </indexterm>
+        <function>btrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
+        <parameter>bytesremoved</parameter> <type>bytea</type> )
+        <returnvalue>bytea</returnvalue>
+       </para>
+       <para>
+        Removes the longest string containing only bytes appearing in
+        <parameter>bytesremoved</parameter> from the start and end of
+        <parameter>bytes</parameter>.
+       </para>
+       <para>
+        <literal>btrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
+        <returnvalue>\x345678</returnvalue>
+       </para></entry>
+      </row>
+
+       <row>
+        <entry role="func_table_entry"><para role="func_signature">
+         <indexterm>
+          <primary>ltrim</primary>
+         </indexterm>
+         <function>ltrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
+         <parameter>bytesremoved</parameter> <type>bytea</type> )
+         <returnvalue>bytea</returnvalue>
+        </para>
+        <para>
+         Removes the longest string containing only bytes appearing in
+         <parameter>bytesremoved</parameter> from the start of
+         <parameter>bytes</parameter>.
+        </para>
+        <para>
+         <literal>ltrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
+         <returnvalue>\x34567890</returnvalue>
+        </para></entry>
+       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
          <primary>octet_length</primary>
         </indexterm>
         <function>octet_length</function> ( <type>bytea</type> )
@@ -4196,6 +4236,26 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
        </para></entry>
       </row>
 
+       <row>
+        <entry role="func_table_entry"><para role="func_signature">
+         <indexterm>
+          <primary>rtrim</primary>
+         </indexterm>
+         <function>rtrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
+         <parameter>bytesremoved</parameter> <type>bytea</type> )
+         <returnvalue>bytea</returnvalue>
+        </para>
+        <para>
+         Removes the longest string containing only bytes appearing in
+         <parameter>bytesremoved</parameter> from the end of
+         <parameter>bytes</parameter>.
+        </para>
+        <para>
+         <literal>rtrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
+         <returnvalue>\x12345678</returnvalue>
+        </para></entry>
+       </row>
+
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
@@ -4309,26 +4369,6 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
-         <primary>btrim</primary>
-        </indexterm>
-        <function>btrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
-        <parameter>bytesremoved</parameter> <type>bytea</type> )
-        <returnvalue>bytea</returnvalue>
-       </para>
-       <para>
-        Removes the longest string containing only bytes appearing in
-        <parameter>bytesremoved</parameter> from the start and end of
-        <parameter>bytes</parameter>.
-       </para>
-       <para>
-       <literal>btrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
-       <returnvalue>\x345678</returnvalue>
-      </para></entry>
-     </row>
-
-      <row>
-       <entry role="func_table_entry"><para role="func_signature">
-        <indexterm>
          <primary>get_bit</primary>
         </indexterm>
         <function>get_bit</function> ( <parameter>bytes</parameter> <type>bytea</type>,
@@ -4407,26 +4447,6 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
       </row>
 
       <row>
-        <entry role="func_table_entry"><para role="func_signature">
-         <indexterm>
-          <primary>ltrim</primary>
-         </indexterm>
-         <function>ltrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
-         <parameter>bytesremoved</parameter> <type>bytea</type> )
-         <returnvalue>bytea</returnvalue>
-        </para>
-        <para>
-         Removes the longest string containing only bytes appearing in
-         <parameter>bytesremoved</parameter> from the start of
-         <parameter>bytes</parameter>.
-        </para>
-        <para>
-         <literal>ltrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
-         <returnvalue>\x34567890</returnvalue>
-        </para></entry>
-       </row>
-
-      <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
          <primary>md5</primary>
@@ -4445,26 +4465,6 @@ SELECT format('Testing %3$s, %2$s, %s', 'one', 'two', 'three');
       </row>
 
       <row>
-        <entry role="func_table_entry"><para role="func_signature">
-         <indexterm>
-          <primary>rtrim</primary>
-         </indexterm>
-         <function>rtrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
-         <parameter>bytesremoved</parameter> <type>bytea</type> )
-         <returnvalue>bytea</returnvalue>
-        </para>
-        <para>
-         Removes the longest string containing only bytes appearing in
-         <parameter>bytesremoved</parameter> from the end of
-         <parameter>bytes</parameter>.
-        </para>
-        <para>
-         <literal>rtrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
-         <returnvalue>\x12345678</returnvalue>
-        </para></entry>
-       </row>
-
-      <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
          <primary>set_bit</primary>
@@ -18354,16 +18354,14 @@ SELECT NULLIF(value, '(none)') ...
     largest or smallest value from a list of any number of expressions.
     The expressions must all be convertible to a common data type, which
     will be the type of the result
-    (see <xref linkend="typeconv-union-case"/> for details).  NULL values
-    in the list are ignored.  The result will be NULL only if all the
-    expressions evaluate to NULL.
+    (see <xref linkend="typeconv-union-case"/> for details).
    </para>
 
    <para>
-    Note that <function>GREATEST</function> and <function>LEAST</function> are not in
-    the SQL standard, but are a common extension.  Some other databases
-    make them return NULL if any argument is NULL, rather than only when
-    all are NULL.
+    NULL values in the argument list are ignored.  The result will be NULL
+    only if all the expressions evaluate to NULL.  (This is a deviation from
+    the SQL standard.  According to the standard, the return value is NULL if
+    any argument is NULL.  Some other databases behave this way.)
    </para>
   </sect2>
  </sect1>