user defined aggregate functions

Hi,
i have a great problem.
I need a user defined aggregate functions, producing a collection type as a result. Does anybody know whether this is possible? If not, is there another way to solve the problem?

Problem:
table test
 id value

  1      1
  1      2
  1      10
  2      3
  2      6 

select id, myudag(value) from test group by id;

should result in two rows.

     1
1 2

     10

2 3

     6 Received on Fri Apr 05 2002 - 14:35:49 CST