363 lines
11 KiB
Plaintext
363 lines
11 KiB
Plaintext
<!--
|
|
doc/src/sgml/ref/create_table_as.sgml
|
|
PostgreSQL documentation
|
|
-->
|
|
|
|
<refentry id="sql-createtableas">
|
|
<indexterm zone="sql-createtableas">
|
|
<primary>CREATE TABLE AS</primary>
|
|
</indexterm>
|
|
|
|
<refmeta>
|
|
<refentrytitle>CREATE TABLE AS</refentrytitle>
|
|
<manvolnum>7</manvolnum>
|
|
<refmiscinfo>SQL - Language Statements</refmiscinfo>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>CREATE TABLE AS</refname>
|
|
<refpurpose>define a new table from the results of a query</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<synopsis>
|
|
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] <replaceable>table_name</replaceable>
|
|
[ (<replaceable>column_name</replaceable> [, ...] ) ]
|
|
[ USING <replaceable class="parameter">method</replaceable> ]
|
|
[ WITH ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] ) | WITHOUT OIDS ]
|
|
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
|
|
[ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
|
|
AS <replaceable>query</replaceable>
|
|
[ WITH [ NO ] DATA ]
|
|
</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>
|
|
|
|
<para>
|
|
<command>CREATE TABLE AS</command> requires <literal>CREATE</literal>
|
|
privilege on the schema used for the table.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Parameters</title>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><literal>GLOBAL</literal> or <literal>LOCAL</literal></term>
|
|
<listitem>
|
|
<para>
|
|
Ignored for compatibility. Use of these keywords is deprecated;
|
|
refer to <xref linkend="sql-createtable"/> for details.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><literal>TEMPORARY</literal> or <literal>TEMP</literal></term>
|
|
<listitem>
|
|
<para>
|
|
If specified, the table is created as a temporary table.
|
|
Refer to <xref linkend="sql-createtable"/> for details.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>UNLOGGED</literal></term>
|
|
<listitem>
|
|
<para>
|
|
If specified, the table is created as an unlogged table.
|
|
Refer to <xref linkend="sql-createtable"/> for details.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>IF NOT EXISTS</literal></term>
|
|
<listitem>
|
|
<para>
|
|
Do not throw an error if a relation with the same name already
|
|
exists; simply issue a notice and leave the table unmodified.
|
|
</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><literal>USING <replaceable class="parameter">method</replaceable></literal></term>
|
|
<listitem>
|
|
<para>
|
|
This optional clause specifies the table access method to use to store
|
|
the contents for the new table; the method needs be an access method of
|
|
type <literal>TABLE</literal>. See <xref linkend="tableam"/> for more
|
|
information. If this option is not specified, the default table access
|
|
method is chosen for the new table. See <xref
|
|
linkend="guc-default-table-access-method"/> for more information.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>WITH ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )</literal></term>
|
|
<listitem>
|
|
<para>
|
|
This clause specifies optional storage parameters for the new table;
|
|
see <xref linkend="sql-createtable-storage-parameters"/> in the
|
|
<xref linkend="sql-createtable"/> documentation for more
|
|
information. For backward-compatibility the <literal>WITH</literal>
|
|
clause for a table can also include <literal>OIDS=FALSE</literal> to
|
|
specify that rows of the new table should contain no OIDs (object
|
|
identifiers), <literal>OIDS=TRUE</literal> is not supported anymore.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>WITHOUT OIDS</literal></term>
|
|
<listitem>
|
|
<para>
|
|
This is backward-compatible syntax for declaring a table
|
|
<literal>WITHOUT OIDS</literal>, creating a table <literal>WITH
|
|
OIDS</literal> is not supported anymore.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>ON COMMIT</literal></term>
|
|
<listitem>
|
|
<para>
|
|
The behavior of temporary tables at the end of a transaction
|
|
block can be controlled using <literal>ON COMMIT</literal>.
|
|
The three options are:
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><literal>PRESERVE ROWS</literal></term>
|
|
<listitem>
|
|
<para>
|
|
No special action is taken at the ends of transactions.
|
|
This is the default behavior.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>DELETE ROWS</literal></term>
|
|
<listitem>
|
|
<para>
|
|
All rows in the temporary table will be deleted at the end
|
|
of each transaction block. Essentially, an automatic <link
|
|
linkend="sql-truncate"><command>TRUNCATE</command></link> is done
|
|
at each commit.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>DROP</literal></term>
|
|
<listitem>
|
|
<para>
|
|
The temporary table will be dropped at the end of the current
|
|
transaction block.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist></para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>TABLESPACE <replaceable class="parameter">tablespace_name</replaceable></literal></term>
|
|
<listitem>
|
|
<para>
|
|
The <replaceable class="parameter">tablespace_name</replaceable> is the name
|
|
of the tablespace in which the new table is to be created.
|
|
If not specified,
|
|
<xref linkend="guc-default-tablespace"/> is consulted, or
|
|
<xref linkend="guc-temp-tablespaces"/> if the table is temporary.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><replaceable>query</replaceable></term>
|
|
<listitem>
|
|
<para>
|
|
A <link linkend="sql-select"><command>SELECT</command></link>, <link
|
|
linkend="sql-table"><command>TABLE</command></link>, or <link linkend="sql-values"><command>VALUES</command></link>
|
|
command, or an <link linkend="sql-execute"><command>EXECUTE</command></link> command that runs a
|
|
prepared <command>SELECT</command>, <command>TABLE</command>, or
|
|
<command>VALUES</command> query.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><literal>WITH [ NO ] DATA</literal></term>
|
|
<listitem>
|
|
<para>
|
|
This clause specifies whether or not the data produced by the query
|
|
should be copied into the new table. If not, only the table structure
|
|
is copied. The default is to copy the data.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Notes</title>
|
|
|
|
<para>
|
|
This command is functionally similar 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. Furthermore, <command>CREATE
|
|
TABLE AS</command> offers a superset of the functionality offered
|
|
by <command>SELECT INTO</command>.
|
|
</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Examples</title>
|
|
|
|
<para>
|
|
Create a new table <literal>films_recent</literal> consisting of only
|
|
recent entries from the table <literal>films</literal>:
|
|
|
|
<programlisting>
|
|
CREATE TABLE films_recent AS
|
|
SELECT * FROM films WHERE date_prod >= '2002-01-01';
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
To copy a table completely, the short form using
|
|
the <literal>TABLE</literal> command can also be used:
|
|
|
|
<programlisting>
|
|
CREATE TABLE films2 AS
|
|
TABLE films;
|
|
</programlisting>
|
|
</para>
|
|
|
|
<para>
|
|
Create a new temporary table <literal>films_recent</literal>, consisting of
|
|
only recent entries from the table <literal>films</literal>, using a
|
|
prepared statement. The new table will be dropped at commit:
|
|
|
|
<programlisting>
|
|
PREPARE recentfilms(date) AS
|
|
SELECT * FROM films WHERE date_prod > $1;
|
|
CREATE TEMP TABLE films_recent ON COMMIT DROP AS
|
|
EXECUTE recentfilms('2002-01-01');
|
|
</programlisting></para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Compatibility</title>
|
|
|
|
<para>
|
|
<command>CREATE TABLE AS</command> conforms to the <acronym>SQL</acronym>
|
|
standard. The following are nonstandard extensions:
|
|
|
|
<itemizedlist spacing="compact">
|
|
<listitem>
|
|
<para>
|
|
The standard requires parentheses around the subquery clause; in
|
|
<productname>PostgreSQL</productname>, these parentheses are
|
|
optional.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
In the standard, the <literal>WITH [ NO ] DATA</literal> clause
|
|
is required; in PostgreSQL it is optional.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para><productname>PostgreSQL</productname> handles temporary tables in a way
|
|
rather different from the standard; see
|
|
<xref linkend="sql-createtable"/>
|
|
for details.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
The <literal>WITH</literal> clause is a <productname>PostgreSQL</productname>
|
|
extension; storage parameters are not in the standard.
|
|
</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>
|
|
The <productname>PostgreSQL</productname> concept of tablespaces is not
|
|
part of the standard. Hence, the clause <literal>TABLESPACE</literal>
|
|
is an extension.
|
|
</para>
|
|
</listitem>
|
|
</itemizedlist></para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
|
|
<simplelist type="inline">
|
|
<member><xref linkend="sql-creatematerializedview"/></member>
|
|
<member><xref linkend="sql-createtable"/></member>
|
|
<member><xref linkend="sql-execute"/></member>
|
|
<member><xref linkend="sql-select"/></member>
|
|
<member><xref linkend="sql-selectinto"/></member>
|
|
<member><xref linkend="sql-values"/></member>
|
|
</simplelist>
|
|
</refsect1>
|
|
|
|
</refentry>
|