CREATE TABLE AS
CREATE TABLE AS — define a new table from the results of a query
Synopsis
CREATE [persistence_mode] TABLE [ IF NOT EXISTS ]table_name[ (column_name[, ...] ) ] [ USINGmethod] [ WITH (storage_parameter[=value] [, ... ] ) | WITHOUT OIDS ] [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ] [ TABLESPACEtablespace_name] ASquery[ WITH [ NO ] DATA ] wherepersistence_modeis: { [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } } | UNLOGGED
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.
CREATE TABLE AS requires CREATE
privilege on the schema used for the table.
Parameters
GLOBALorLOCALIgnored for compatibility. Use of these keywords is deprecated; refer to CREATE TABLE for details.
TEMPORARYorTEMPIf specified, the table is created as a temporary table. Refer to CREATE TABLE for details.
UNLOGGEDIf specified, the table is created as an unlogged table. Refer to CREATE TABLE for details.
IF NOT EXISTSDo not throw an error if a relation with the same name already exists; simply issue a notice and leave the table unmodified.
table_nameThe name (optionally schema-qualified) of the table to be created.
column_nameThe 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.
USINGmethodThis 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
TABLE. See Chapter 62 for more information. If this option is not specified, the default table access method is chosen for the new table. See default_table_access_method for more information.WITH (storage_parameter[=value] [, ... ] )This clause specifies optional storage parameters for the new table; see Storage Parameters in the CREATE TABLE documentation for more information. For backward-compatibility the
WITHclause for a table can also includeOIDS=FALSEto specify that rows of the new table should contain no OIDs (object identifiers),OIDS=TRUEis not supported anymore.WITHOUT OIDSThis is backward-compatible syntax for declaring a table
WITHOUT OIDS, creating a tableWITH OIDSis not supported anymore.ON COMMITThe behavior of temporary tables at the end of a transaction block can be controlled using
ON COMMIT. The three options are:PRESERVE ROWSNo special action is taken at the ends of transactions. This is the default behavior.
DELETE ROWSAll rows in the temporary table will be deleted at the end of each transaction block. Essentially, an automatic
TRUNCATEis done at each commit.DROPThe temporary table will be dropped at the end of the current transaction block.
TABLESPACEtablespace_nameThe
tablespace_nameis the name of the tablespace in which the new table is to be created. If not specified, default_tablespace is consulted, or temp_tablespaces if the table is temporary.queryA
SELECT,TABLE, orVALUEScommand, or anEXECUTEcommand that runs a preparedSELECT,TABLE, orVALUESquery.WITH [ NO ] DATAThis 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.
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.
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 will be dropped at commit:
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');
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 ] DATAclause 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
WITHclause is a PostgreSQL extension; storage parameters are not in the standard.The PostgreSQL concept of tablespaces is not part of the standard. Hence, the clause
TABLESPACEis an extension.
See Also
CREATE MATERIALIZED VIEW, CREATE TABLE, EXECUTE, SELECT, SELECT INTO, VALUESReport a documentation issue
Read the upstream documentation. For corrections, first check the current manual.