Nested tables and multiset operators in Oracle 10g

Question

Consider the following scenario:
We have two identical relations R and S defined as:
CREATE TABLE R(
a INTEGER,
b table_type)
NESTED TABLE b STORE as b_1;
CREATE TABLE S(
a INTEGER,
b table_type)
NESTED TABLE b STORE as b_2;
where table_typ is defined as
CREATE TYPE table_typ AS TABLE OF VARCHAR2(8);
Suppose we have two instances of R and S, each having one tuple as follows: R(1,table_typ('a','b')) and S(1,table_typ('b','c')).
I would like to "merge" these two simple instances (e.g., achieve the effect of a simple SELECT * FROM R UNION SELECT * FROM S query) and obtain the following resulting instance: Result(1,table_typ('a','b','c')).
Would this be possible in Oracle 10g? A simple UNION does not work (I got a "inconsistent datatypes: expected - got SCOTT.TABLE_TYP" error). I also took a look at the MULTISET UNION operator over nested tables available in Oracle 10g, but it doesn't seem to get me anywhere. Any help on this would be greatly appreciated.
Thank you,
Laura

Answer 1

Oracle Database 10g Enterprise Edition Release 10.1.0.2.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SQL> CREATE OR REPLACE TYPE table_type AS TABLE OF VARCHAR2 (8);
  2  /
Type created.
SQL> CREATE TABLE r(
  2    a INTEGER,
  3    b table_type)
  4    NESTED TABLE b STORE as b_1;
Table created.
SQL> CREATE TABLE s(
  2    a INTEGER,
  3    b table_type)
  4    NESTED TABLE b STORE as b_2;
Table created.
SQL> INSERT INTO r VALUES (1, table_type ('a', 'b'));
1 row created.
SQL> INSERT INTO s VALUES (1, table_type ('b', 'c'));
1 row created.
SQL> COLUMN c FORMAT A10;
SQL> SELECT r.a, r.b MULTISET UNION DISTINCT s.b c
  2  FROM   r, s
  3  WHERE  r.a = s.a;
         A C
         1 TABLE_TYPE('a', 'b', 'c')
SQL>