CREATE TABLE AS
CREATE TABLE AS — define a new table from the results of a query
Synopsis
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] 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 ]
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.
CREATE TABLE AS
requiresCREATE
privilege on the schema used for the table.
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.
IF NOT EXISTS
Do not throw an error if a relation with the same name already exists; simply issue a notice and leave the table unmodified.
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.
USING
method
This 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
. SeeChapter 61 for more information. If this option is not specified, the default table access method is chosen for the new table. Seedefault_table_access_method for more information.WITH (
storage_parameter
[=value
] [, ... ] )This clause specifies optional storage parameters for the new table; seeStorage Parameters in theCREATE TABLE documentation for more information. For backward-compatibility the
WITH
clause for a table can also includeOIDS=FALSE
to specify that rows of the new table should contain no OIDs (object identifiers),OIDS=TRUE
is not supported anymore.WITHOUT OIDS
This is backward-compatible syntax for declaring a table
WITHOUT OIDS
, creating a tableWITH OIDS
is not supported anymore.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
is done at each commit.DROP
The temporary table will be dropped at the end of the current transaction block.
TABLESPACE
tablespace_name
The
tablespace_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
A
SELECT
,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
.
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 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
The standard requires parentheses around the subquery clause; inPostgreSQL, these parentheses are optional. In the standard, the PostgreSQL handles temporary tables in a way rather different from the standard; seeCREATE TABLE for details. The ThePostgreSQL concept of tablespaces is not part of the standard. Hence, the clauseCREATE TABLE AS
conforms to theSQL standard. The following are nonstandard extensions:WITH [ NO ] DATA
clause is required; in PostgreSQL it is optional.WITH
clause is aPostgreSQL extension; storage parameters are not in the standard.TABLESPACE
is an extension.