doc/src/sgml/ref/drop_aggregate.sgml

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   2 doc/src/sgml/ref/drop_aggregate.sgml
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   5
   6 <refentry id="sql-dropaggregate">
   7  <indexterm zone="sql-dropaggregate">
   8   <primary>DROP AGGREGATE</primary>
   9  </indexterm>
  10
  11  <refmeta>
  12   <refentrytitle>DROP AGGREGATE</refentrytitle>
  13   <manvolnum>7</manvolnum>
  14   <refmiscinfo>SQL - Language Statements</refmiscinfo>
  15  </refmeta>
  16
  17  <refnamediv>
  18   <refname>DROP AGGREGATE</refname>
  19   <refpurpose>remove an aggregate function</refpurpose>
  20  </refnamediv>
  21
  22  <refsynopsisdiv>
  23 <synopsis>
  24 DROP AGGREGATE [ IF EXISTS ] <replaceable>name</replaceable> ( <replaceable>aggregate_signature</replaceable> ) [, ...] [ CASCADE | RESTRICT ]
  25
  26 <phrase>where <replaceable>aggregate_signature</replaceable> is:</phrase>
  27
  28 * |
  29 [ <replaceable>argmode</replaceable> ] [ <replaceable>argname</replaceable> ] <replaceable>argtype</replaceable> [ , ... ] |
  30 [ [ <replaceable>argmode</replaceable> ] [ <replaceable>argname</replaceable> ] <replaceable>argtype</replaceable> [ , ... ] ] ORDER BY [ <replaceable>argmode</replaceable> ] [ <replaceable>argname</replaceable> ] <replaceable>argtype</replaceable> [ , ... ]
  31 </synopsis>
  32  </refsynopsisdiv>
  33
  34  <refsect1>
  35   <title>Description</title>
  36
  37   <para>
  38    <command>DROP AGGREGATE</command> removes an existing
  39    aggregate function. To execute this command the current
  40    user must be the owner of the aggregate function.
  41   </para>
  42  </refsect1>
  43
  44  <refsect1>
  45   <title>Parameters</title>
  46
  47   <variablelist>
  48
  49    <varlistentry>
  50     <term><literal>IF EXISTS</literal></term>
  51     <listitem>
  52      <para>
  53       Do not throw an error if the aggregate does not exist. A notice is issued
  54       in this case.
  55      </para>
  56     </listitem>
  57    </varlistentry>
  58
  59    <varlistentry>
  60     <term><replaceable class="parameter">name</replaceable></term>
  61     <listitem>
  62      <para>
  63       The name (optionally schema-qualified) of an existing aggregate function.
  64      </para>
  65     </listitem>
  66    </varlistentry>
  67
  68    <varlistentry>
  69     <term><replaceable class="parameter">argmode</replaceable></term>
  70
  71     <listitem>
  72      <para>
  73       The mode of an argument: <literal>IN</literal> or <literal>VARIADIC</literal>.
  74       If omitted, the default is <literal>IN</literal>.
  75      </para>
  76     </listitem>
  77    </varlistentry>
  78
  79    <varlistentry>
  80     <term><replaceable class="parameter">argname</replaceable></term>
  81
  82     <listitem>
  83      <para>
  84       The name of an argument.
  85       Note that <command>DROP AGGREGATE</command> does not actually pay
  86       any attention to argument names, since only the argument data
  87       types are needed to determine the aggregate function's identity.
  88      </para>
  89     </listitem>
  90    </varlistentry>
  91
  92    <varlistentry>
  93     <term><replaceable class="parameter">argtype</replaceable></term>
  94     <listitem>
  95      <para>
  96       An input data type on which the aggregate function operates.
  97       To reference a zero-argument aggregate function, write <literal>*</literal>
  98       in place of the list of argument specifications.
  99       To reference an ordered-set aggregate function, write
 100       <literal>ORDER BY</literal> between the direct and aggregated argument
 101       specifications.
 102      </para>
 103     </listitem>
 104    </varlistentry>
 105
 106    <varlistentry>
 107     <term><literal>CASCADE</literal></term>
 108     <listitem>
 109      <para>
 110       Automatically drop objects that depend on the aggregate function
 111       (such as views using it),
 112       and in turn all objects that depend on those objects
 113       (see <xref linkend="ddl-depend"/>).
 114      </para>
 115     </listitem>
 116    </varlistentry>
 117
 118    <varlistentry>
 119     <term><literal>RESTRICT</literal></term>
 120     <listitem>
 121      <para>
 122       Refuse to drop the aggregate function if any objects depend on
 123       it.  This is the default.
 124      </para>
 125     </listitem>
 126    </varlistentry>
 127   </variablelist>
 128  </refsect1>
 129
 130  <refsect1>
 131   <title>Notes</title>
 132
 133    <para>
 134     Alternative syntaxes for referencing ordered-set aggregates
 135     are described under <xref linkend="sql-alteraggregate"/>.
 136    </para>
 137  </refsect1>
 138
 139  <refsect1>
 140   <title>Examples</title>
 141
 142   <para>
 143    To remove the aggregate function <literal>myavg</literal> for type
 144    <type>integer</type>:
 145 <programlisting>
 146 DROP AGGREGATE myavg(integer);
 147 </programlisting>
 148   </para>
 149
 150   <para>
 151    To remove the hypothetical-set aggregate function <literal>myrank</literal>,
 152    which takes an arbitrary list of ordering columns and a matching list
 153    of direct arguments:
 154 <programlisting>
 155 DROP AGGREGATE myrank(VARIADIC "any" ORDER BY VARIADIC "any");
 156 </programlisting>
 157   </para>
 158
 159   <para>
 160    To remove multiple aggregate functions in one command:
 161 <programlisting>
 162 DROP AGGREGATE myavg(integer), myavg(bigint);
 163 </programlisting></para>
 164 </refsect1>
 165
 166  <refsect1>
 167   <title>Compatibility</title>
 168
 169   <para>
 170    There is no <command>DROP AGGREGATE</command> statement in the SQL
 171    standard.
 172   </para>
 173  </refsect1>
 174
 175  <refsect1>
 176   <title>See Also</title>
 177
 178   <simplelist type="inline">
 179    <member><xref linkend="sql-alteraggregate"/></member>
 180    <member><xref linkend="sql-createaggregate"/></member>
 181   </simplelist>
 182  </refsect1>
 183
 184 </refentry>