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Make the CREATE TABLE ref page more readable and update some information.

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Peter Eisentraut
2001-10-22 18:14:47 +00:00
parent e97fe98c36
commit f08c9ff84b
5 changed files with 865 additions and 2143 deletions
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245
doc/src/sgml/ref/create_table_as.sgml
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@@ -1,112 +1,26 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table_as.sgml,v 1.7 2001/09/03 12:57:49 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_table_as.sgml,v 1.8 2001/10/22 18:14:47 petere Exp $
Postgres documentation
-->
<refentry id="SQL-CREATETABLEAS">
<refmeta>
<refentrytitle id="SQL-CREATETABLEAS-TITLE">
CREATE TABLE AS
</refentrytitle>
<refentrytitle>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>
<refname>CREATE TABLE AS</refname>
<refpurpose>create a new table from the results of a query</refpurpose>
</refnamediv>
<refsynopsisdiv>
<refsynopsisdivinfo>
<date>2001-03-03</date>
</refsynopsisdivinfo>
<synopsis>
CREATE [ TEMPORARY | TEMP ] TABLE <replaceable>table</replaceable> [ (<replaceable>column</replaceable> [, ...] ) ]
AS <replaceable>select_clause</replaceable>
<synopsis>
CREATE [ [ LOCAL ] { TEMPORARY | TEMP } ] TABLE <replaceable>table_name</replaceable> [ (<replaceable>column_name</replaceable> [, ...] ) ]
AS <replaceable>query</replaceable>
</synopsis>
<refsect2>
<refsect2info>
<date>1998-09-22</date>
</refsect2info>
<title>
Inputs
</title>
<para>
<variablelist>
<varlistentry>
<term>TEMPORARY or TEMP</term>
<listitem>
<para>
If specified, the 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>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>
<varlistentry>
<term><replaceable>column</replaceable></term>
<listitem>
<para>
The name of a column. Multiple column names can be specified using
a comma-delimited list of column names. If column names are not
provided, they are taken from the output column names of the
SELECT query.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>select_clause</replaceable></term>
<listitem>
<para>
A valid query statement. Refer to
<xref linkend="sql-select" endterm="sql-select-title">
for a description of the allowed syntax.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect2>
<refsect2>
<refsect2info>
<date>1998-09-22</date>
</refsect2info>
<title>
Outputs
</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>
</refsect2>
</refsynopsisdiv>
<refsect1>
<refsect1info>
<date>2001-03-20</date>
@@ -117,28 +31,135 @@ CREATE [ TEMPORARY | TEMP ] TABLE <replaceable>table</replaceable> [ (<replaceab
<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 datatypes associated with 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 <command>SELECT</command> column names by giving
an explicit list of column names).
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 <command>SELECT</command> just once to fill the new table
initially. The new table will not track subsequent changes to
the source tables of the <command>SELECT</command>. In contrast,
a view re-evaluates the given <command>SELECT</command> whenever queried.
</para>
<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.
<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 the
underlying <command>SELECT</command> statements whenever it is
queried.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><literal>[LOCAL] TEMPORARY</> or <literal>[LOCAL] TEMP</></term>
<listitem>
<para>
If specified, the table is created as a temporary table.
Temporary tables are automatically dropped at the end of a
session. Existing persistent tables with the same name are not
visible to the current session while the temporary table exists.
Any indexes created on a temporary table are automatically
temporary as well.
</para>
<para>
The <literal>LOCAL</literal> word is optional.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable>table_name</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>
<varlistentry>
<term><replaceable>column_name</replaceable></term>
<listitem>
<para>
The name of a column in the new table. Multiple column names can
be specified using a comma-delimited list of column names. 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">
for a description of the allowed syntax.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Diagnostics</title>
<para>
Refer to <xref linkend="sql-createtable"> and
<xref linkend="sql-select">
for a summary of possible output messages.
</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
This command is functionally equivalent to <xref
linkend="sql-selectinto">, 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
SQL92 or SQL99. 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>History</title>
<para>
The <command>CREATE TABLE AS</command> command has been available
since <productname>PostgreSQL</productname> 6.3.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-createtable"></member>
<member><xref linkend="sql-createview"></member>
<member><xref linkend="sql-select"></member>
<member><xref linkend="sql-selectinto"></member>
</simplelist>
</refsect1>
</refentry>
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