CREATE TABLE AS

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 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.

Parameters

Notes

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.

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';

To copy a table completely, the short form using the TABLE command can also be used:

CREATE TABLE films2 AS
  TABLE films;

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. The following are nonstandard extensions:

• The standard requires parentheses around the subquery clause; in PostgreSQL, these parentheses are optional.

• In the standard, the WITH [ NO ] DATA clause is required; in PostgreSQL it is optional.

• PostgreSQL handles temporary tables in a way rather different from the standard; see CREATE TABLE 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