Postgres-別の列の合計の結果に基づいて合計を計算する

row_count()を使用しました 連続した行番号が必要なため。通常、主キーにはギャップが含まれている可能性があるため、主キーに依存するべきではありません。

with recursive cte as (
    select *, row_number() over (order by id)
    from measurements
),
work_table as (
    select 
        id,
        count as count_sum,
        volume as volume_sum,
        row_number
    from cte
    where row_number = 1
    union all
    select
        c.id,
        case when w.volume_sum >= 100
            then c.count
            else w.count_sum + c.count
        end as count_sum,
        case
            when w.volume_sum >= 100
            then c.volume
            else w.volume_sum + c.volume
        end as discrete_sum_volume,
        c.row_number
    from cte c
    join work_table w
    on c.row_number = w.row_number + 1
)
select count_sum, volume_sum
from work_table
where volume_sum >= 100
or id = (select max(id) from work_table)
order by id

結果：

 count_sum | volume_sum 
-----------+------------
        87 |        111
        49 |        100
         2 |       16.5
(3 rows)

SqlFiddle。