create table #t(
   id           int,
   seq          int,
   amount       money,
   primary key (id, seq)
)

insert into #t values(1, 1, 10)
insert into #t values(1, 2, -10)
insert into #t values(1, 3, 20)
insert into #t values(1, 4, -10)
insert into #t values(2, 1, 10)
insert into #t values(2, 2, -10)
insert into #t values(2, 3, 10)

alter table #t add balance money null

update #t set balance = (select sum(amount) from #t t2 where #t.id=t2.id and #t.seq>=t2.seq)

delete from #t where exists (select 1 from #t t2 where #t.id=t2.id and #t.seq<t2.seq and balance=0)

delete from #t where balance=0