CREATE TABLE AS
Synopsis
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLEtable_name [ (column_name [, ...] ) ] [ WITH (storage_parameter [=value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ] [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ] [ TABLESPACEtablespace_name ] ASquery [ WITH [ NO ] DATA ]Description
CREATE TABLE AS creates a table and fills it with data computed by aSELECT command. The table columns have the names and data types associated with the output columns of theSELECT (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 definingSELECT statement whenever it is queried.
Parameters
- GLOBAL orLOCAL
Ignored for compatibility. Use of these keywords is deprecated; refer toCREATE TABLE for details.
- TEMPORARY orTEMP
If specified, the table is created as a temporary table. Refer toCREATE TABLE for details.
- UNLOGGED
If specified, the table is created as an unlogged table. Refer toCREATE 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.
- WITH (storage_parameter [=value] [, ... ] )
This clause specifies optional storage parameters for the new table; seeStorage Parameters for more information. TheWITH clause can also includeOIDS=TRUE (or justOIDS) to specify that rows of the new table should have OIDs (object identifiers) assigned to them, orOIDS=FALSE to specify that the rows should not have OIDs. SeeCREATE TABLE for more information.
- WITH OIDS
WITHOUT OIDS These are obsolescent syntaxes equivalent toWITH (OIDS) andWITH (OIDS=FALSE), respectively. If you wish to give both anOIDS setting and storage parameters, you must use theWITH ( ... ) syntax; see above.
- ON COMMIT
The behavior of temporary tables at the end of a transaction block can be controlled usingON 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 automaticTRUNCATE is done at each commit.
- DROP
The temporary table will be dropped at the end of the current transaction block.
- TABLESPACEtablespace_name
Thetablespace_name is the name of the tablespace in which the new table is to be created. If not specified,default_tablespace is consulted, ortemp_tablespaces if the table is temporary.
- query
ASELECT,TABLE, orVALUES command, or anEXECUTE command that runs a preparedSELECT,TABLE, orVALUES query.
- WITH [ NO ] DATA
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.
Notes
This command is functionally similar toSELECT INTO, but it is preferred since it is less likely to be confused with other uses of theSELECT INTO syntax. Furthermore,CREATE TABLE AS offers a superset of the functionality offered bySELECT INTO.
TheCREATE TABLE AS command allows the user to explicitly specify whether OIDs should be included. If the presence of OIDs is not explicitly specified, thedefault_with_oids configuration variable is used.
Examples
Create a new tablefilms_recent consisting of only recent entries from the tablefilms:
CREATE TABLE films_recent AS SELECT * FROM films WHERE date_prod >= '2002-01-01';
To copy a table completely, the short form using theTABLE command can also be used:
CREATE TABLE films2 AS TABLE films;
Create a new temporary tablefilms_recent, consisting of only recent entries from the tablefilms, 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 theSQL standard. The following are nonstandard extensions: The standard requires parentheses around the subquery clause; inPostgreSQL, these parentheses are optional. In the standard, theWITH [ NO ] DATA clause is required; in PostgreSQL it is optional. PostgreSQL handles temporary tables in a way rather different from the standard; seeCREATE TABLE for details. TheWITH clause is aPostgreSQL extension; neither storage parameters nor OIDs are in the standard. ThePostgreSQL concept of tablespaces is not part of the standard. Hence, the clauseTABLESPACE is an extension.