여러줄을 한줄로 표현

with tb as 
( 
select '1111' docno, 1 seqno, 1 prot, 'AAAA' empno from dual union all 
select '1111' , 1 , 2 , 'BBBB' from dual union all 
select '5555' , 3 , 1 , 'KKKK' from dual union all 
select '5555' , 3 , 2 , 'MMMM' from dual union all 
select '5555' , 3 , 3 , 'PPPP' from dual 
) 
select a.docno 
, a.seqno 
, substr(max(sys_connect_by_path(empno,',')),2) as empno 
from ( 
select docno 
, seqno 
, empno 
, row_number() over(partition by docno 
, seqno 
order by rownum) as rn 
from tb) a 
start with rn = 1 
connect by prior rn = rn-1 
and prior docno = docno 
and prior seqno = seqno 
group by docno 
, seqno 
order by docno 
;

/