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drop_aggregate.sgml：源码内容
							<refentry id="SQL-DROPAGGREGATE">
 <refmeta>
  <refentrytitle>
   DROP AGGREGATE
  </refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>
 <refnamediv>
  <refname>
   DROP AGGREGATE
  </refname>
  <refpurpose>
   Removes the definition of an aggregate function
  </refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <refsynopsisdivinfo>
   <date>1998-04-15</date>
  </refsynopsisdivinfo>
  <synopsis>
DROP AGGREGATE <replaceable class="PARAMETER">name</replaceable> <replaceable class="PARAMETER">type</replaceable>
  </synopsis>
  <refsect2 id="R2-SQL-DROPAGGREGATE-1">
   <refsect2info>
    <date>1998-04-15</date>
   </refsect2info>
   <title>
    Inputs
   </title>
   <para>
    <variablelist>
     <varlistentry>
      <term><replaceable class="parameter">name</replaceable></term>
      <listitem>
       <para>
	The name of an existing aggregate function.
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term><replaceable class="parameter">type</replaceable></term>
      <listitem>
       <para>
	The type of an existing aggregate function.
	(Refer to the <citetitle>PostgreSQL User's Guide</citetitle> for
	further information about data types).
	<comment>This should become a cross-reference rather than a
	 hard-coded chapter number</comment>
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>
  </refsect2>
  <refsect2 id="R2-SQL-DROPAGGREGATE-2">
   <refsect2info>
    <date>1998-04-15</date>
   </refsect2info>
   <title>
    Outputs
   </title>
   <para>
    <variablelist>
     <varlistentry>
      <term><computeroutput>
DROP
       </computeroutput></term>
      <listitem>
       <para>
	Message returned if the command is successful.
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term><computeroutput>
WARN RemoveAggregate: aggregate '<replaceable class="parameter">agg</replaceable>' for '<replaceable class="parameter">type</replaceable>' does not exist
       </computeroutput></term>
      <listitem>
       <para>
	This message occurs if the aggregate function specified does not
	exist in the database.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>
  </refsect2>
 </refsynopsisdiv>
 <refsect1 id="R1-SQL-DROPAGGREGATE-1">
  <refsect1info>
   <date>1998-04-15</date>
  </refsect1info>
  <title>
   Description
  </title>
  <para>
   <command>DROP AGGREGATE</command> will remove all references to an existing
   aggregate definition. To execute this command the current
   user must be the owner of the aggregate.
  </para>
  <refsect2 id="R2-SQL-DROPAGGREGATE-3">
   <refsect2info>
    <date>1998-04-15</date>
   </refsect2info>
   <title>
    Notes
   </title>
   <para>
    The <command>DROP AGGREGATE</command> statement is a
    <productname>Postgres</productname>
    language extension.
   </para>
   <para>
    Refer to the <command>CREATE AGGREGATE</command> statement to
    create aggregate functions.
   </para>
  </refsect2>
 </refsect1>
 <refsect1 id="R1-SQL-DROPAGGREGATE-2">
  <title>
   Usage
  </title>
  <para>
   To remove the <literal>myavg</literal> aggregate for type
   <literal>int4</literal>:
  </para>
  <programlisting>
DROP AGGREGATE myavg int4;
  </programlisting>
 </refsect1>
 <refsect1 id="R1-SQL-DROPAGGREGATE-3">
  <title>
   Compatibility
  </title>
  <para>
  </para>
  <refsect2 id="R2-SQL-DROPAGGREGATE-4">
   <refsect2info>
    <date>1998-04-15</date>
   </refsect2info>
   <title>
    SQL92
   </title>
   <para>
    There is no DROP AGGREGATE statement in <acronym>SQL92</acronym>.
   </para>
  </refsect2>
 </refsect1>
</refentry>
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