WITH T AS (
SELECT '111' ID, 'AAA' VAL FROM DUAL UNION ALL
SELECT '111' ID, 'BBB' VAL FROM DUAL UNION ALL
SELECT '222' ID, 'CCC' VAL FROM DUAL UNION ALL
SELECT '222' ID, 'DDD' VAL FROM DUAL
)
SELECT ID,LISTAGG(VAL,',') WITHIN GROUP(ORDER BY 1)
FROM T
GROUP BY ID

WITH t AS
(
SELECT 111 id, 'AAA' v FROM dual
UNION ALL SELECT 111, 'BBB' FROM dual
UNION ALL SELECT 222, 'CCC' FROM dual
UNION ALL SELECT 222, 'DDD' FROM dual
)
SELECT id
     , LISTAGG(v, ',') WITHIN GROUP(ORDER BY v) OVER(PARTITION BY id) x
  FROM t
;