CREATE TABLE AS() SQL Commands CREATE TABLE AS()NAME
CREATE TABLE AS - define a new table from the results of a query
SYNOPSIS
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE table_name
[ (column_name [, ...] ) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace ]
AS query
DESCRIPTION
CREATE TABLE AS creates a table and fills it with data computed by a
SELECT command. The table columns have the names and data types asso‐
ciated with the output columns of the SELECT (except that you can over‐
ride 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.
PARAMETERS
GLOBAL or LOCAL
Ignored for compatibility. Refer to CREATE TABLE [create_ta‐
ble(5)] for details.
TEMPORARY or TEMP
If specified, the table is created as a temporary table. Refer
to CREATE TABLE [create_table(5)] for details.
table_name
The name (optionally schema-qualified) of the table to be cre‐
ated.
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 ( storage_parameter [= value] [, ... ] )
This clause specifies optional storage parameters for the new
table; see Storage Parameters [create_table(5)] for more infor‐
mation. The WITH clause can also include OIDS=TRUE (or just
OIDS) to specify that rows of the new table should have OIDs
(object identifiers) assigned to them, or OIDS=FALSE to specify
that the rows should not have OIDs. See CREATE TABLE [cre‐
ate_table(5)] for more information.
WITH OIDS
WITHOUT OIDS
These are obsolescent syntaxes equivalent to WITH (OIDS) and
WITH (OIDS=FALSE), respectively. If you wish to give both an
OIDS setting and storage parameters, you must use the WITH ( ...
) syntax; see above.
ON COMMIT
The behavior of temporary tables at the end of a transaction
block can be controlled using ON COMMIT. The three options are:
PRESERVE ROWS
No special action is taken at the ends of transactions.
This is the default behavior.
DELETE ROWS
All rows in the temporary table will be deleted at the
end of each transaction block. Essentially, an automatic
TRUNCATE [truncate(5)] is done at each commit.
DROP The temporary table will be dropped at the end of the
current transaction block.
TABLESPACE tablespace
The tablespace is the name of the tablespace in which the new
table is to be created. If not specified, default_tablespace is
used, or the database's default tablespace if default_tablespace
is an empty string.
query A SELECT [select(5)] or VALUES [values(5)] command, or an EXE‐
CUTE [execute(5)] command that runs a prepared SELECT or VALUES
query.
NOTES
This command is functionally similar to SELECT INTO [select_into(5)],
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 iden‐
tical 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.
EXAMPLES
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 a new temporary table films_recent, consisting of only recent
entries from the table films, using a prepared statement. The new table
has OIDs and will be dropped at commit:
PREPARE recentfilms(date) AS
SELECT * FROM films WHERE date_prod > $1;
CREATE TEMP TABLE films_recent WITH (OIDS) ON COMMIT DROP AS
EXECUTE recentfilms('2002-01-01');
COMPATIBILITY
CREATE TABLE AS conforms to the SQL standard, with the following excep‐
tions:
· The standard requires parentheses around the subquery clause; in
PostgreSQL, these parentheses are optional.
· 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 NO DATA can be
simulated by appending LIMIT 0 to the query.
· PostgreSQL handles temporary tables in a way rather different from
the standard; see CREATE TABLE [create_table(5)] for details.
· The WITH clause is a PostgreSQL extension; neither storage parameters
nor OIDs are in the standard.
· The PostgreSQL concept of tablespaces is not part of the standard.
Hence, the clause TABLESPACE is an extension.
SEE ALSO
CREATE TABLE [create_table(5)], EXECUTE [execute(l)], SELECT
[select(l)], SELECT INTO [select_into(l)], VALUES [values(l)]
SQL - Language Statements 2008-01-03 CREATE TABLE AS()
