CREATE TABLE AS — define a new table from the results of a query
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLEtable_name
[ (column_name
[, ...] ) ] [ [ WITH | WITHOUT ] OIDS ] ASquery
CREATE TABLE AS
creates a table and fills it
with data computed by a SELECT
command or an
EXECUTE
that runs a prepared
SELECT
command. The table columns have the
names and data types associated with the output columns of the
SELECT
(except that you can override the column
names by giving an explicit list of new column names).
CREATE TABLE AS
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 SELECT
statement whenever it is
queried.
GLOBAL
or LOCAL
Ignored for compatibility. Refer to CREATE TABLE for details.
TEMPORARY
or TEMP
If specified, the table is created as a temporary table. Refer to CREATE TABLE for details.
table_name
The name (optionally schema-qualified) of the table to be created.
column_name
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. If the table is created from an
EXECUTE
command, a column name list cannot be
specified.
WITH OIDS
WITHOUT OIDS
This optional clause specifies whether the table created by
CREATE TABLE AS
should include OIDs. If
neither form of this clause is specified, the value of the
default_with_oids configuration parameter is
used.
query
A query statement (that is, a SELECT
command
or an EXECUTE
command that runs a prepared
SELECT
command). Refer to SELECT or EXECUTE,
respectively, for a description of the allowed syntax.
This command is functionally similar to SELECT INTO, but it is
preferred since it is less likely to be confused with other uses of
the SELECT INTO
syntax. Furthermore, CREATE
TABLE AS
offers a superset of the functionality offered
by SELECT INTO
.
Prior to PostgreSQL 8.0, CREATE
TABLE AS
always included OIDs in the table it
created. As of PostgreSQL 8.0,
the CREATE TABLE AS
command allows the user to
explicitly specify whether OIDs should be included. If the
presence of OIDs is not explicitly specified,
the default_with_oids configuration variable is
used. As of PostgreSQL 8.1,
this variable is false by default, so the default behavior is not
identical to pre-8.0 releases. Applications that
require OIDs in the table created by CREATE TABLE
AS
should explicitly specify WITH OIDS
to ensure proper behavior.
Create a new table films_recent
consisting of only
recent entries from the table films
:
CREATE TABLE films_recent AS SELECT * FROM films WHERE date_prod >= '2002-01-01';
CREATE TABLE AS
conforms to the SQL
standard, with the following exceptions:
The standard requires parentheses around the subquery clause; in PostgreSQL, these parentheses are optional.
The standard defines an ON COMMIT
clause;
this is not currently implemented by PostgreSQL.
The standard defines a WITH [ NO ] DATA
clause;
this is not currently implemented by PostgreSQL.
The behavior provided by PostgreSQL is equivalent
to the standard's WITH DATA
case.
WITH/WITHOUT OIDS
is a PostgreSQL
extension.
PostgreSQL handles temporary tables in a way rather different from the standard; see CREATE TABLE for details.