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bb4eefe7bf
DocBook XML is superficially compatible with DocBook SGML but has a slightly stricter DTD that we have been violating in a few cases. Although XSLT doesn't care whether the document is valid, the style sheets don't necessarily process invalid documents correctly, so we need to work toward fixing this. This first commit moves the indexterms in refentry elements to an allowed position. It has no impact on the output.
176 lines
4.6 KiB
Plaintext
176 lines
4.6 KiB
Plaintext
<!--
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doc/src/sgml/ref/drop_aggregate.sgml
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PostgreSQL documentation
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-->
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<refentry id="SQL-DROPAGGREGATE">
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<indexterm zone="sql-dropaggregate">
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<primary>DROP AGGREGATE</primary>
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</indexterm>
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<refmeta>
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<refentrytitle>DROP AGGREGATE</refentrytitle>
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<manvolnum>7</manvolnum>
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<refmiscinfo>SQL - Language Statements</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>DROP AGGREGATE</refname>
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<refpurpose>remove an aggregate function</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<synopsis>
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DROP AGGREGATE [ IF EXISTS ] <replaceable>name</replaceable> ( <replaceable>aggregate_signature</replaceable> ) [ CASCADE | RESTRICT ]
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<phrase>where <replaceable>aggregate_signature</replaceable> is:</phrase>
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* |
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[ <replaceable>argmode</replaceable> ] [ <replaceable>argname</replaceable> ] <replaceable>argtype</replaceable> [ , ... ] |
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[ [ <replaceable>argmode</replaceable> ] [ <replaceable>argname</replaceable> ] <replaceable>argtype</replaceable> [ , ... ] ] ORDER BY [ <replaceable>argmode</replaceable> ] [ <replaceable>argname</replaceable> ] <replaceable>argtype</replaceable> [ , ... ]
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</synopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>
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<command>DROP AGGREGATE</command> removes an existing
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aggregate function. To execute this command the current
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user must be the owner of the aggregate function.
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</para>
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</refsect1>
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<refsect1>
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<title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><literal>IF EXISTS</literal></term>
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<listitem>
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<para>
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Do not throw an error if the aggregate does not exist. A notice is issued
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in this case.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="parameter">name</replaceable></term>
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<listitem>
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<para>
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The name (optionally schema-qualified) of an existing aggregate function.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="parameter">argmode</replaceable></term>
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<listitem>
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<para>
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The mode of an argument: <literal>IN</> or <literal>VARIADIC</>.
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If omitted, the default is <literal>IN</>.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="parameter">argname</replaceable></term>
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<listitem>
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<para>
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The name of an argument.
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Note that <command>DROP AGGREGATE</command> does not actually pay
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any attention to argument names, since only the argument data
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types are needed to determine the aggregate function's identity.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="parameter">argtype</replaceable></term>
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<listitem>
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<para>
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An input data type on which the aggregate function operates.
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To reference a zero-argument aggregate function, write <literal>*</>
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in place of the list of argument specifications.
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To reference an ordered-set aggregate function, write
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<literal>ORDER BY</> between the direct and aggregated argument
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specifications.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>CASCADE</literal></term>
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<listitem>
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<para>
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Automatically drop objects that depend on the aggregate function.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>RESTRICT</literal></term>
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<listitem>
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<para>
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Refuse to drop the aggregate function if any objects depend on
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it. This is the default.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>
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Alternative syntaxes for referencing ordered-set aggregates
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are described under <xref linkend="sql-alteraggregate">.
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</para>
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</refsect1>
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<refsect1>
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<title>Examples</title>
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<para>
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To remove the aggregate function <literal>myavg</literal> for type
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<type>integer</type>:
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<programlisting>
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DROP AGGREGATE myavg(integer);
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</programlisting>
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</para>
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<para>
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To remove the hypothetical-set aggregate function <literal>myrank</>,
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which takes an arbitrary list of ordering columns and a matching list
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of direct arguments:
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<programlisting>
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DROP AGGREGATE myrank(VARIADIC "any" ORDER BY VARIADIC "any");
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</programlisting>
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</para>
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</refsect1>
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<refsect1>
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<title>Compatibility</title>
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<para>
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There is no <command>DROP AGGREGATE</command> statement in the SQL
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standard.
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</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<simplelist type="inline">
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<member><xref linkend="sql-alteraggregate"></member>
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<member><xref linkend="sql-createaggregate"></member>
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</simplelist>
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</refsect1>
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</refentry>
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