select_into.sgml

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$Header: /cvsroot/pgsql/doc/src/sgml/ref/select_into.sgml,v 1.16 2002/01/20 22:19:57 petere Exp $
PostgreSQL documentation
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<refentry id="SQL-SELECTINTO">
 <refmeta>
  <refentrytitle id="SQL-SELECTINTO-TITLE">
   SELECT INTO
  </refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>
 <refnamediv>
  <refname>
   SELECT INTO
  </refname>
  <refpurpose>
   create a new table from the results of a query
  </refpurpose></refnamediv>
 <refsynopsisdiv>
  <refsynopsisdivinfo>
   <date>2000-12-11</date>
  </refsynopsisdivinfo>
  <synopsis>
SELECT [ ALL | DISTINCT [ ON ( <replaceable class="PARAMETER">expression</replaceable> [, ...] ) ] ]
    * | <replaceable class="PARAMETER">expression</replaceable> [ AS <replaceable class="PARAMETER">output_name</replaceable> ] [, ...]
    INTO [ TEMPORARY | TEMP ] [ TABLE ] <replaceable class="PARAMETER">new_table</replaceable>
    [ FROM <replaceable class="PARAMETER">from_item</replaceable> [, ...] ]
    [ WHERE <replaceable class="PARAMETER">condition</replaceable> ]
    [ GROUP BY <replaceable class="PARAMETER">expression</replaceable> [, ...] ]
    [ HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
    [ { UNION | INTERSECT | EXCEPT } [ ALL ] <replaceable class="PARAMETER">select</replaceable> ]
    [ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] [, ...] ]
    [ FOR UPDATE [ OF <replaceable class="PARAMETER">tablename</replaceable> [, ...] ] ]
    [ LIMIT [ <replaceable class="PARAMETER">start</replaceable> , ] { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
    [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]

where <replaceable class="PARAMETER">from_item</replaceable> can be:

[ ONLY ] <replaceable class="PARAMETER">table_name</replaceable> [ * ]
    [ [ AS ] <replaceable class="PARAMETER">alias</replaceable> [ ( <replaceable class="PARAMETER">column_alias_list</replaceable> ) ] ]
|
( <replaceable class="PARAMETER">select</replaceable> )
    [ AS ] <replaceable class="PARAMETER">alias</replaceable> [ ( <replaceable class="PARAMETER">column_alias_list</replaceable> ) ]
|
<replaceable class="PARAMETER">from_item</replaceable> [ NATURAL ] <replaceable class="PARAMETER">join_type</replaceable> <replaceable class="PARAMETER">from_item</replaceable>
    [ ON <replaceable class="PARAMETER">join_condition</replaceable> | USING ( <replaceable class="PARAMETER">join_column_list</replaceable> ) ]
  </synopsis>
  
  <refsect2 id="R2-SQL-SELECTINTO-1">
   <refsect2info>
    <date>2001-03-20</date>
   </refsect2info>
   <title>
    Inputs
   </title>

   <para>
    <variablelist>
    <varlistentry>
     <term>TEMPORARY</term>
     <term>TEMP</term>
     <listitem>
      <para>
	If TEMPORARY or TEMP is specified,
	the output table is created only within this session, and is
	automatically dropped on session exit.
	Existing permanent tables with the same name are not visible
	(in this session) while the temporary table exists.
	Any indexes created on a temporary table are automatically
	temporary as well.
      </para>
     </listitem>
    </varlistentry>

     <varlistentry>
      <term><replaceable class="PARAMETER">new_table</replaceable></term>
      <listitem>
       <para>
        The name of the new table to be created.
	This table must not already exist.  However, a temporary table
	can be created that has the same name as an existing permanent
	table.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </para>

   <para>
    All other inputs are described in detail for
    <xref linkend="sql-select">.
   </para>
  </refsect2>

  <refsect2 id="R2-SQL-SELECTINTO-2">
   <refsect2info>
    <date>2001-03-20</date>
   </refsect2info>
   <title>
    Outputs
   </title>

   <para>
    Refer to
    <xref linkend="sql-createtable">
    and
    <xref linkend="sql-select">
    for a summary of possible output messages.
   </para>
  </refsect2>
 </refsynopsisdiv>

 <refsect1 id="R1-SQL-SELECTINTO-1">
  <refsect1info>
   <date>2001-03-20</date>
  </refsect1info>
  <title>
   Description
  </title>

  <para>
   <command>SELECT INTO</command> creates a new table and fills it
   with data computed by a query.  The data is not returned to the
   client, as it is with a normal <command>SELECT</command>.  The new
   table's columns have the names and data types associated with the
   output columns of the <command>SELECT</command>.

   <note>
    <para>
     <xref linkend="sql-createtableas">
     is functionally equivalent to <command>SELECT INTO</command>.
     <command>CREATE TABLE AS</command> is the recommended syntax, since
     <command>SELECT INTO</command> is not standard.  In fact, this form of
     <command>SELECT INTO</command> is not available in <application>PL/pgSQL</application> or <xref linkend="app-ecpg">,
     because they interpret the INTO clause differently.
    </para>
   </note>
  </para>
 </refsect1>

 <refsect1 id="R1-SQL-SELECTINTO-2">
  <title>
   Compatibility
  </title>

   <para>
    SQL92 uses <command>SELECT ... INTO</command> to represent selecting
    values into scalar variables of a host program, rather than creating
    a new table.  This indeed is the usage found in <application>PL/pgSQL</application> and <xref linkend="app-ecpg">.
    The <productname>PostgreSQL</productname> usage of <command>SELECT
    INTO</command> to represent table creation is historical.  It's best
    to use <command>CREATE TABLE AS</command> for this purpose in new code.
    (<command>CREATE TABLE AS</command> isn't standard either, but it's
    less likely to cause confusion.)
    </para>
 </refsect1>
</refentry>

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