Cumulative Querry

create table a (key_col int, val int);

insert into a values (1, 10);
insert into a values (2, 10);
insert into a values (3, 30);
insert into a values (4, 10);
insert into a values (5, -20);


select x.key_col, x.val,
 sum(y.val) as cumulated
from a x
inner join a y on x.key_col >= y.key_col
group by x.key_col,x.val
order by x.key_col,x.val;

Drop table a;