Limit SQL query results by distinct column value

Question

I have an table with columns id, score, parent_id ordered by the score.

id	score	parent_id
5859	10	5859
2157043	9	5859
21064154	8	21064154
51992	7	51992
34384599	6	51992
1675761	5	1675761
3465729	4	3465729
401202	3	401203
1817458	2	1817458

I want to query all columns from this table with the same order but limit results at least 5 rows to meet the unique parent_id number equal to 5. As result, the parent_id only contains 5 ids: 5859, 21064154, 51992, 1675761, 3465729

Expected Results like:

id	score	parent_id
5859	10	5859
2157043	9	5859
21064154	8	21064154
51992	7	51992
34384599	6	51992
1675761	5	1675761
3465729	4	3465729

Answer 1

One other way you could accomplish this is to use lag to indicate when the id changes and then use a cumulative sum over a window then filtering accordingly:

select id, score, parent_id
from (
  select *, Sum(diff) over(order by score desc)seq
  from (
     select *, 
       case when Lag(parent_id) over(order by score desc) = parent_id then 0 else 1 end diff
    from t
  )t
)d
where seq <= 5
order by score desc;