字符串太长转换为分段显示

模拟创建数据：

create table zy_1 (username varchar2(30));
insert into zy_1 (USERNAME)
values ('ZHOUXIN014');

insert into zy_1 (USERNAME)
values ('EDSAFCSOP');

insert into zy_1 (USERNAME)
values ('AGENTJOB');

insert into zy_1 (USERNAME)
values ('SALESLOGTMP');

insert into zy_1 (USERNAME)
values ('EDSLASSOP');

insert into zy_1 (USERNAME)
values ('SALESJOB');

insert into zy_1 (USERNAME)
values ('AFCSSYNOPR');

insert into zy_1 (USERNAME)
values ('FRETSOPR');

insert into zy_1 (USERNAME)
values ('ICSJOB');

sql代码：

-- Created on 2013-1-27 by XL 
--CREATE DIRECTORY D_OUTPUT AS 'E:';
declare
  -- Local variables here
  V_FILE UTL_FILE.FILE_TYPE;
  V_BUFFER VARCHAR2(32767);
  v_user clob:='';
begin
  -- Test statements here
  V_FILE := UTL_FILE.FOPEN('D_OUTPUT', 'schema.txt', 'w', 32767);
  for cc in (select usert
               from (select lev,
                            r2,
                            ltrim(sys_connect_by_path(username, ','), ',') as usert,
                            id3
                       from (select username,
                                    lev,
                                    r2,
                                    row_number() over(partition by lev order by lev, r2) as id1,
                                    lag(username) over(partition by lev order by lev, r2) as par_user,
                                    max(r2) over(partition by lev) as id3
                               from (select username,
                                            trunc(r1 / 4) lev,
                                            mod(r1, 4) as r2
                                       from (select username, rownum as r1
                                               from zy_1)))
                      start with par_user is null
                     connect by prior username = par_user)
              where r2 = id3) loop
     v_user:=v_user||cc.usert||',';
  end loop;
  UTL_FILE.PUT_LINE(V_FILE, v_user);
  UTL_FILE.FCLOSE(V_FILE);
end;