Creating a table from a query

CREATE TABLE can specify an AS clause to create a table from a query, as follows:.

CREATE TABLE can specify an AS clause to create a table from a query, as follows:

CREATE [TEMPORARY] TABLE [schema.]table-name
    [ ( column-name-list ) ]
    [ {INCLUDE | EXCLUDE} [SCHEMA] PRIVILEGES ]
AS  [  /*+ LABEL */ ] [ AT epoch ] query [ ENCODED BY column-ref-list ]

Vertica creates a table from the query results and loads the result set into it. For example:

=> CREATE TABLE cust_basic_profile AS SELECT
     customer_key, customer_gender, customer_age, marital_status, annual_income, occupation
     FROM customer_dimension WHERE customer_age>18 AND customer_gender !='';
CREATE TABLE
=> SELECT customer_age, annual_income, occupation FROM cust_basic_profile
     WHERE customer_age > 23 ORDER BY customer_age;
 customer_age | annual_income |     occupation
--------------+---------------+--------------------
           24 |        469210 | Hairdresser
           24 |        140833 | Butler
           24 |        558867 | Lumberjack
           24 |        529117 | Mechanic
           24 |        322062 | Acrobat
           24 |        213734 | Writer
           ...

AS clause options

You can qualify an AS clause with one or both of the following options:

  • LABEL hint that identifies a statement for profiling and debugging

  • AT epoch clause to specify that the query return historical data

Labeling the AS clause

You can embed a LABEL hint in an AS clause in two places:

  • Immediately after the keyword AS:

    CREATE TABLE myTable AS /*+LABEL myLabel*/...

  • In the SELECT statement:

    CREATE TABLE myTable AS SELECT /*+LABEL myLabel*/

If the AS clause contains a LABEL hint in both places, the first label has precedence.

Loading historical data

You can qualify a CREATE TABLE AS query with an AT epoch clause, to specify that the query return historical data, where epoch is one of the following:

  • EPOCH LATEST: Return data up to but not including the current epoch. The result set includes data from the latest committed DML transaction.

  • EPOCH integer: Return data up to and including the integer-specified epoch.

  • TIME 'timestamp': Return data from the timestamp-specified epoch.

See Epochs for additional information about how Vertica uses epochs.

For details, see Historical queries.

Zero-width column handling

If the query returns a column with zero width, Vertica automatically converts it to a VARCHAR(80) column. For example:

=> CREATE TABLE example AS SELECT '' AS X;
CREATE TABLE
=> SELECT EXPORT_TABLES ('', 'example');
                       EXPORT_TABLES
----------------------------------------------------------
CREATE TEMPORARY TABLE public.example
(
    X varchar(80)
);

Requirements and restrictions

  • If you create a temporary table from a query, you must specify ON COMMIT PRESERVE ROWS in order to load the result set into the table. Otherwise, Vertica creates an empty table.

  • If the query output has expressions other than simple columns, such as constants or functions, you must specify an alias for that expression, or list all columns in the column name list.

  • You cannot use CREATE TABLE AS SELECT with a SELECT that returns values of complex types. You can, however, use CREATE TABLE LIKE.

See also