POWERMULTISET

Syntax

Description of the illustration powermultiset.eps

Purpose

POWERMULTISET takes as input a nested table and returns a nested table of nested tables containing all nonempty subsets (called submultisets) of the input nested table.

• expr can be any expression that evaluates to a nested table.

• If expr resolves to null, then Oracle Database returns NULL.

• If expr resolves to a nested table that is empty, then Oracle returns an error.

• The element types of the nested table must be comparable. Refer to "Comparison Conditions" for information on the comparability of nonscalar types.

  Note:

  This function is not supported in PL/SQL.

Examples

First, create a data type that is a nested table of the cust_address_tab_type data type:

CREATE TYPE cust_address_tab_tab_typ
  AS TABLE OF cust_address_tab_typ;
/

Now, select the nested table column cust_address_ntab from the customers_demo table using the POWERMULTISET function:

SELECT CAST(POWERMULTISET(cust_address_ntab) AS cust_address_tab_tab_typ)
  FROM customers_demo;

CAST(POWERMULTISET(CUST_ADDRESS_NTAB) AS CUST_ADDRESS_TAB_TAB_TYP)
  (STREET_ADDRESS, POSTAL_CODE, CITY, STATE_PROVINCE, COUNTRY_ID)
------------------------------------------------------------------
CUST_ADDRESS_TAB_TAB_TYP(CUST_ADDRESS_TAB_TYP(CUST_ADDRESS_TYP
  ('514 W Superior St', '46901', 'Kokomo', 'IN', 'US')))
CUST_ADDRESS_TAB_TAB_TYP(CUST_ADDRESS_TAB_TYP(CUST_ADDRESS_TYP
  ('2515 Bloyd Ave', '46218', 'Indianapolis', 'IN', 'US')))
CUST_ADDRESS_TAB_TAB_TYP(CUST_ADDRESS_TAB_TYP(CUST_ADDRESS_TYP
  ('8768 N State Rd 37', '47404', 'Bloomington', 'IN', 'US')))
CUST_ADDRESS_TAB_TAB_TYP(CUST_ADDRESS_TAB_TYP(CUST_ADDRESS_TYP
  ('6445 Bay Harbor Ln', '46254', 'Indianapolis', 'IN', 'US')))
. . .

The preceding example requires the customers_demo table and a nested table column containing data. Refer to "Multiset Operators" to create this table and nested table columns.