postgresql/doc/src/sgml/ref/create_table_as.sgml

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<refentry id="SQL-CREATETABLEAS">
 <refmeta>
  <refentrytitle id="sql-createtableas-title">CREATE TABLE AS</refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>CREATE TABLE AS</refname>
  <refpurpose>create a new table from the results of a query</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name</replaceable> [ (<replaceable>column_name</replaceable> [, ...] ) ]
    AS <replaceable>query</replaceable>
</synopsis>
 </refsynopsisdiv>
  
 <refsect1>
  <title>Description</title>

  <para>
   <command>CREATE TABLE AS</command> creates a table and fills it
   with data computed by a <command>SELECT</command> command.  The
   table columns have the names and data types associated with the
   output columns of the <command>SELECT</command> (except that you
   can override the column names by giving an explicit list of new
   column names).
  </para>

  <para>
   <command>CREATE TABLE AS</command> bears some resemblance to
   creating a view, but it is really quite different: it creates a new
   table and evaluates the query just once to fill the new table
   initially.  The new table will not track subsequent changes to the
   source tables of the query.  In contrast, a view re-evaluates its
   defining <command>SELECT</command> statement whenever it is
   queried.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>
   
  <variablelist>
   <varlistentry>
    <term><literal>TEMPORARY</> or <literal>TEMP</></term>
    <listitem>
     <para>
      If specified, the table is created as a temporary table.
      Refer to <xref linkend="sql-createtable" endterm="sql-createtable-title"> for details.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable>table_name</replaceable></term>
    <listitem>
     <para>
      The name (optionally schema-qualified) of the table to be created.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable>column_name</replaceable></term>
    <listitem>
     <para>
      The name of a column in the new table.  If column names are not
      provided, they are taken from the output column names of the
      query.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable>query</replaceable></term>
    <listitem>
     <para>
      A query statement (that is, a <command>SELECT</command>
      command).  Refer to
      <xref linkend="sql-select" endterm="sql-select-title">
      for a description of the allowed syntax.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Diagnostics</title>

  <para>
   Refer to <xref linkend="sql-createtable" endterm="sql-createtable-title"> and
   <xref linkend="sql-select" endterm="sql-select-title">
   for a summary of possible output messages.
  </para>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   This command is functionally equivalent to <xref
   linkend="sql-selectinto" endterm="sql-selectinto-title">, but it is preferred since it is less
   likely to be confused with other uses of the <command>SELECT
   ... INTO</command> syntax.
  </para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   This command is modeled after an <productname>Oracle</productname>
   feature.  There is no command with equivalent functionality in
   the SQL standard.  However, a combination of <literal>CREATE
   TABLE</literal> and <literal>INSERT ... SELECT</literal> can
   accomplish the same thing with little more effort.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createtable" endterm="sql-createtable-title"></member>
   <member><xref linkend="sql-createview" endterm="sql-createview-title"></member>
   <member><xref linkend="sql-select" endterm="sql-select-title"></member>
   <member><xref linkend="sql-selectinto" endterm="sql-selectinto-title"></member>
  </simplelist>
 </refsect1>
 
</refentry>

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