How to summarize days by a flag field?

Question

How can I summarize the days Kyle has on this table using a flag field?

Row	Name	Flag	Days
1	Kyle	0	12
2	Kyle	0	02
3	Kyle	1	01
4	Kyle	1	18
5	Kyle	1	01
6	Kyle	0	01
7	Kyle	1	01
8	Kyle	1	01

I want this result:

Row	Name	Flag	Days
1	Kyle	0	12
2	Kyle	0	02
3	Kyle	1	20
6	Kyle	0	01
7	Kyle	1	02

Answer 1

This reads like a gaps-and-island problem. If I follow this correctly, we can identify "adjacent" rows with the difference between row numbers, then aggregate islands whose flag is enabled:

select min(row) as row, name, flag, sum(days) as days
from (
    select t.*,
        row_number() over(partition by name order by row) rn1,
        row_number() over(partition by name, flag order by row) rn2
    from mytable t
) t
group by name, flag, 
    case when flag = 1 then rn1 - rn2 else row end
order by 1

Demo on DB Fiddle (credits to nbk for creating the use case).