concatenate strings in a query

Sometimes I have to do reports that take a table like that (silly example):

CREATE TABLE SILLY_EXAMPLE (
   KEY INTEGER,
   DATA VARCHAR2(4000)
) ;

INSERT INTO SILLY_EXAMPLE VALUES (1,'AAA');
INSERT INTO SILLY_EXAMPLE VALUES (1,'BBB');
INSERT INTO SILLY_EXAMPLE VALUES (1,'CCC');

INSERT INTO SILLY_EXAMPLE VALUES (2,'XXX'); INSERT INTO SILLY_EXAMPLE VALUES (2,'YYY'); and give an output like that:

Key Data
--- --------------
1 AAA,BBB,CCC
2 XXX,YYY I always solved using PL/SQL and a for..loop cursor with some logic inside the loop. I'm wondering if it's possible (with Oracle 9.0.1) to do the report with a single SQL query.

Kind regards,

-- 
Cris Carampa (spamto:cris119_at_operamail.com)
"Welcome to the new world order
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