问SQL严格集子集

EN

with concatenated_to as (
select from_id, array_agg(to_id) as arr_to
from t
group by from_id
)
select c1.from_id,c2.from_id 
from concatenated_to c1
join concatenated_to c2 on c1.from_id<>c2.from_id
where c2.arr_to <@ c1.arr_to

select t.from_id, t2.from_id
from (select t.*, count(*) over (partition by from_id) as cnt
      from t
     ) t left join
     (select t.*, count(*) over (partition by from_id) as cnt
      from t
     ) t2
     on t.to_id = t2.to_id and t2.cnt = t.cnt
group by t.from_id, t2.from_id
having count(*) = count(t2.from_id);