Set function in PLSQL?

The new SET function in 10g returns a distinct range of elements from a collection (i.e. DISTINCT). For simple collections such as the one we have used throughout this article, it's very straightforward, as the following example demonstrates.

SQL> SELECT nt

  2  ,      SET(nt) AS nt_set

  3  FROM (

  4        SELECT varchar2_ntt('A','B','C','C') AS nt

  5        FROM dual

  6       );

NT                                  NT_SET

----------------------------------- ------------------------------

VARCHAR2_NTT('A', 'B', 'C', 'C')    VARCHAR2_NTT('A', 'B', 'C')

1 row selected.

SQL> SELECT nt.column_value AS distinct_element

  2  FROM   TABLE(SET(varchar2_ntt('A','B','C','C'))) nt;

DISTINCT_ELEMENT

----------------

A

B

C

3 rows selected.