Oracle 18c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
CREATE TABLE table_name (
  key1 NUMBER,
  key2 NUMBER,
  foo  VARCHAR2(20),
  bar  VARCHAR2(20)
)
INSERT INTO table_name (key1, key2, foo, bar)
select 1, 2, '1.0', 'A' from dual UNION ALL
select 1, 2, '2.0', 'A' from dual UNION ALL
select 3, 4, '2.0', 'A' from dual UNION ALL
select 3, 4, '2.0', 'B' from dual UNION ALL
select 3, 4, '2.0', 'B' from dual;
5 rows affected

SELECT key1,
       key2,
       JSON_ARRAYAGG(foo) foo,
       JSON_ARRAYAGG(bar) bar
FROM   table_name
GROUP BY key1, key2


KEY1
KEY2
FOO
BAR


1
2
["1.0","2.0"]
["A","A"]

3
4
["2.0","2.0","2.0"]
["A","B","B"]


SELECT key1,
       key2,
       ( SELECT JSON_ARRAYAGG(COLUMN_VALUE)
         FROM   TABLE(t.foos) ) AS foo,
       ( SELECT JSON_ARRAYAGG(COLUMN_VALUE)
         FROM   TABLE(t.bars) ) AS bar
FROM   (
  SELECT key1,
         key2,
         CAST(COLLECT(DISTINCT foo) AS SYS.ODCIVARCHAR2LIST) AS foos,
         CAST(COLLECT(DISTINCT bar) AS SYS.ODCIVARCHAR2LIST) AS bars
  FROM   table_name
  GROUP BY key1, key2
) t


KEY1
KEY2
FOO
BAR


1
2
["1.0","2.0"]
["A"]

3
4
["2.0"]
["A","B"]