mirror of
https://github.com/postgres/postgres.git
synced 2025-12-22 17:42:17 +03:00
0d3f4406df
There's no inherent reason why an aggregate function can't be variadic (even VARIADIC ANY) if its transition function can handle the case. Indeed, this patch to add the feature touches none of the planner or executor, and little of the parser; the main missing stuff was DDL and pg_dump support. It is true that variadic aggregates can create the same sort of ambiguity about parameters versus ORDER BY keys that was complained of when we (briefly) had both one- and two-argument forms of string_agg(). However, the policy formed in response to that discussion only said that we'd not create any built-in aggregates with varying numbers of arguments, not that we shouldn't allow users to do it. So the logical extension of that is we can allow users to make variadic aggregates as long as we're wary about shipping any such in core. In passing, this patch allows aggregate function arguments to be named, to the extent of remembering the names in pg_proc and dumping them in pg_dump. You can't yet call an aggregate using named-parameter notation. That seems like a likely future extension, but it'll take some work, and it's not what this patch is really about. Likewise, there's still some work needed to make window functions handle VARIADIC fully, but I left that for another day. initdb forced because of new aggvariadic field in Aggref parse nodes.
176 lines
5.1 KiB
Plaintext
176 lines
5.1 KiB
Plaintext
<!--
|
|
doc/src/sgml/ref/alter_aggregate.sgml
|
|
PostgreSQL documentation
|
|
-->
|
|
|
|
<refentry id="SQL-ALTERAGGREGATE">
|
|
<refmeta>
|
|
<refentrytitle>ALTER AGGREGATE</refentrytitle>
|
|
<manvolnum>7</manvolnum>
|
|
<refmiscinfo>SQL - Language Statements</refmiscinfo>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>ALTER AGGREGATE</refname>
|
|
<refpurpose>change the definition of an aggregate function</refpurpose>
|
|
</refnamediv>
|
|
|
|
<indexterm zone="sql-alteraggregate">
|
|
<primary>ALTER AGGREGATE</primary>
|
|
</indexterm>
|
|
|
|
<refsynopsisdiv>
|
|
<synopsis>
|
|
ALTER AGGREGATE <replaceable>name</replaceable> ( [ <replaceable>argmode</replaceable> ] [ <replaceable>arg_name</replaceable> ] <replaceable>arg_data_type</replaceable> [ , ... ] )
|
|
RENAME TO <replaceable>new_name</replaceable>
|
|
ALTER AGGREGATE <replaceable>name</replaceable> ( [ <replaceable>argmode</replaceable> ] [ <replaceable>arg_name</replaceable> ] <replaceable>arg_data_type</replaceable> [ , ... ] )
|
|
OWNER TO <replaceable>new_owner</replaceable>
|
|
ALTER AGGREGATE <replaceable>name</replaceable> ( [ <replaceable>argmode</replaceable> ] [ <replaceable>arg_name</replaceable> ] <replaceable>arg_data_type</replaceable> [ , ... ] )
|
|
SET SCHEMA <replaceable>new_schema</replaceable>
|
|
</synopsis>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>
|
|
<command>ALTER AGGREGATE</command> changes the definition of an
|
|
aggregate function.
|
|
</para>
|
|
|
|
<para>
|
|
You must own the aggregate function to use <command>ALTER AGGREGATE</>.
|
|
To change the schema of an aggregate function, you must also have
|
|
<literal>CREATE</literal> privilege on the new schema.
|
|
To alter the owner, you must also be a direct or indirect member of the new
|
|
owning role, and that role must have <literal>CREATE</literal> privilege on
|
|
the aggregate function's schema. (These restrictions enforce that altering
|
|
the owner doesn't do anything you couldn't do by dropping and recreating
|
|
the aggregate function. However, a superuser can alter ownership of any
|
|
aggregate function anyway.)
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Parameters</title>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">name</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
The name (optionally schema-qualified) of an existing aggregate function.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">argmode</replaceable></term>
|
|
|
|
<listitem>
|
|
<para>
|
|
The mode of an argument: <literal>IN</> or <literal>VARIADIC</>.
|
|
If omitted, the default is <literal>IN</>.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">arg_name</replaceable></term>
|
|
|
|
<listitem>
|
|
<para>
|
|
The name of an argument.
|
|
Note that <command>ALTER AGGREGATE</command> does not actually pay
|
|
any attention to argument names, since only the argument data
|
|
types are needed to determine the aggregate function's identity.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">arg_data_type</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
An input data type on which the aggregate function operates.
|
|
To reference a zero-argument aggregate function, write <literal>*</>
|
|
in place of the list of argument specifications.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">new_name</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
The new name of the aggregate function.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">new_owner</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
The new owner of the aggregate function.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable class="parameter">new_schema</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
The new schema for the aggregate function.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Examples</title>
|
|
|
|
<para>
|
|
To rename the aggregate function <literal>myavg</literal> for type
|
|
<type>integer</type> to <literal>my_average</literal>:
|
|
<programlisting>
|
|
ALTER AGGREGATE myavg(integer) RENAME TO my_average;
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
To change the owner of the aggregate function <literal>myavg</literal> for type
|
|
<type>integer</type> to <literal>joe</literal>:
|
|
<programlisting>
|
|
ALTER AGGREGATE myavg(integer) OWNER TO joe;
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
To move the aggregate function <literal>myavg</literal> for type
|
|
<type>integer</type> into schema <literal>myschema</literal>:
|
|
<programlisting>
|
|
ALTER AGGREGATE myavg(integer) SET SCHEMA myschema;
|
|
</programlisting></para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Compatibility</title>
|
|
|
|
<para>
|
|
There is no <command>ALTER AGGREGATE</command> statement in the SQL
|
|
standard.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
|
|
<simplelist type="inline">
|
|
<member><xref linkend="sql-createaggregate"></member>
|
|
<member><xref linkend="sql-dropaggregate"></member>
|
|
</simplelist>
|
|
</refsect1>
|
|
</refentry>
|