Oracle 18c

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create table qty_split (
  "ORDER" varchar2(4),
  article_code varchar2(4), 
  size_1 number(3,0),
  size_2 number(3,0),
  size_3 number(3,0)
);
insert into qty_split 
SELECT 'a001', '1111', 123, 165, 85 FROM DUAL UNION ALL
SELECT 'b002', '2222', 312, 45, 17 FROM DUAL UNION ALL
SELECT 'c003', '3333', 0, 0, 417 FROM DUAL;
3 rows affected

WITH data ( "ORDER", article, size_1, size_2, size_3 ) AS (
  SELECT * FROM qty_split
UNION ALL
  SELECT "ORDER",
         article,
         GREATEST( size_1 - 99, 0 ),
         GREATEST( size_2 - 99, 0 ),
         GREATEST( size_3 - 99, 0 )
  FROM   data
  WHERE  size_1 > 99
  OR     size_2 > 99
  OR     size_3 > 99
)
SELECT "ORDER",
       article,
       LEAST( size_1, 99 ) AS size_1,
       LEAST( size_2, 99 ) AS size_2,
       LEAST( size_3, 99 ) AS size_3
FROM   data
ORDER BY
       "ORDER",
       article,
       ROWNUM;


ORDER
ARTICLE
SIZE_1
SIZE_2
SIZE_3


a001
1111
99
99
85

a001
1111
24
66
0

b002
2222
99
45
17

b002
2222
99
0
0

b002
2222
99
0
0

b002
2222
15
0
0

c003
3333
0
0
99

c003
3333
0
0
99

c003
3333
0
0
99

c003
3333
0
0
99

c003
3333
0
0
21

ORDER	ARTICLE	SIZE_1	SIZE_2	SIZE_3
a001	1111	99	99	85
a001	1111	24	66	0
b002	2222	99	45	17
b002	2222	99	0	0
b002	2222	99	0	0
b002	2222	15	0	0
c003	3333	0	0	99
c003	3333	0	0	99
c003	3333	0	0	99
c003	3333	0	0	99
c003	3333	0	0	21