How To on Select Query

Question

I have following table.
Id     Amount
1     30
2     20
3     10
4     10
5     30
6     10
7     20     
8     10
i need following output
sum
60     sum where id <=3
100     sum where id <=5          
140     sum where id <=8
how can i achieve this?

Answer 1

  1  with v as (
  2     select 1 id, 30 amount from dual union all
  3     select 2, 20 from dual union all
  4     select 3, 10 from dual union all
  5     select 4, 10 from dual union all
  6     select 5, 30 from dual union all
  7     select 6, 10 from dual union all
  8     select 7, 20 from dual union all
  9     select 8, 10 from dual
10  )
11  select dsc, sum
12  from (
13     select id
14     , 'Sum where id <= '||id dsc
15     , sum(amount) over (
16        order by id
17     ) sum
18     from v
19  )
20* where id in (3, 5, 8)
SQL> /
DSC                         SUM
Sum where id <= 3            60
Sum where id <= 5           100
Sum where id <= 8           140
3 rows selected.