Comment puis-je me débarrasser de "ORA-01489: résultat de la concaténation de chaîne est trop long" dans cette requête?

cette requête est dominant, jeux en réseau. ainsi, par exemple, étant donné un réseau

A<----->B
B<----->C
B<----->D
C<----->E
D<----->C
D<----->E
F<----->E

il retourne

B,E

B,F

A,E

mais il ne fonctionne pas de données pour les grandes, parce que je suis à l'aide de méthodes string dans mon résultat. j'ai essayé de supprimer la chaîne de méthodes et de revenir à une vue ou quelque chose, mais en vain

With t as (select 'A' as per1, 'B' as per2 from dual union all
select 'B','C' from dual union all
select 'B','D' from dual union all
select 'C','B' from dual union all
select 'C','E' from dual union all
select 'D','C' from dual union all
select 'D','E' from dual union all
select 'E','C' from dual union all
select 'E','D' from dual union all
select 'F','E' from dual)
,t2 as (select distinct least(per1, per2) as per1, greatest(per1, per2) as per2 from t union
select distinct greatest(per1, per2) as per1, least(per1, per2) as per1 from t)
,t3 as (select per1, per2, row_number() over (partition by per1 order by per2) as rn from t2)
,people as (select per, row_number() over (order by per) rn
from (select distinct per1 as per from t union
select distinct per2 from t)
)
,comb   as (select sys_connect_by_path(per,',')||',' as p
from   people
connect by rn > prior rn
)
,find   as (select p, per2, count(*) over (partition by p) as cnt
from (
select distinct comb.p, t3.per2
from   comb, t3
where  instr(comb.p, ','||t3.per1||',') > 0 or instr(comb.p, ','||t3.per2||',') > 0
)
)
,rnk as (select p, rank() over (order by length(p)) as rnk
from find
where cnt = (select count(*) from people)
order by rnk
)  select distinct trim(',' from p) as p from rnk  where rnk.rnk = 1`