How to produce correct SQL result?

Question

PostgreSQL

Good afternoon! There is a table product(id, option) and it looks something like this
id | option
1 | 1
1 | 2
2 | 1
2 | 3
3 | 2
...
How to form a request in such a way as to display, for example, a product with options 1, 2?

Answer 1

SELECT id FROM  T  where o =1 and id in (select id from t where o=2)

option two:

select id from (
  select id, max(o1) as o1, max(o2) as o2 from (
      select id,1 as o1, 0 as o2 from T where o = 1
    union
      select id,0 as o1, 1 as o2 from T where o = 2
  ) as T1 group by id
) as T2
where o1=1 and o2=1