create table part_coments (
  id number,
  comments varchar2(2000),
  creation_date date);
  
insert into part_coments values(1,'abc1','1-Jul-2008');
insert into part_coments values(1,'abc2','2-Jul-2008');
insert into part_coments values(1,'abc3','3-Jul-2008');
insert into part_coments values(2,'abc','1-Jul-2008');

commit;

id , comments
1    abc1. abc2. abc3
2    abc

SELECT	id,
   	     MAX (SUBSTR (SYS_CONNECT_BY_PATH (comments, '/'), 2)) AS comments
   FROM    (SELECT id, comments,
   		     ROW_NUMBER () OVER (PARTITION BY id ORDER BY ROWID) AS rn
   	      FROM    part_coments)
   GROUP   BY id
   START   WITH rn = 1
   CONNECT BY PRIOR id = id AND PRIOR rn = rn - 1
   ORDER   BY id

SELECT	id,
   	     SUBSTR (SYS_CONNECT_BY_PATH (comments, '/'), 2) AS comments
   FROM    (SELECT id, comments,
   		     ROW_NUMBER () OVER (PARTITION BY id ORDER BY NULL) AS rn,
                     COUNT(*) OVER (PARTITION BY id) cnt
   	      FROM    part_coments)
   WHERE rn = cnt
   START   WITH rn = 1
   CONNECT BY PRIOR id = id AND PRIOR rn = rn - 1
   ORDER   BY id

SELECT	id,
   	     SUBSTR (SYS_CONNECT_BY_PATH (comments, CHR(10)), 2) AS comments
   FROM    (SELECT id, comments,
   		     ROW_NUMBER () OVER (PARTITION BY id ORDER BY NULL) AS rn,
                     COUNT(*) OVER (PARTITION BY id) cnt
   	      FROM    part_coments)
   WHERE rn = cnt
   START   WITH rn = 1
   CONNECT BY PRIOR id = id AND PRIOR rn = rn - 1

issueno | comments | creationdate
1       | some comments | 1-Jan-2008
1       | some more comments | 1-Jan-2008

issueno | comments
1       | some comments <line feed or chr(10)>
        | some more comments