[SQL] how can i get this result....??(accumulation distinct count)

Question

[SQL] how can i get this result....??(accumulation distinct count)
Hi everybody,
pls tell me how can it possible to get result?
### sample data
date visitor
10-01 A
10-01 A
10-01 B
10-01 B
10-01 C
10-01 C
10-02 A
10-02 C
10-02 C
10-02 D
10-02 D
10-03 B
10-03 B
10-03 B
10-03 A
10-03 A
10-03 F
10-04 A
10-04 A
10-04 F
result that i want...like this.
date date_unqiue_visitors acc_date_unique_visitors
10-01 3 3
10-02 3 4
10-03 3 5
10-04 2 5
date distinct visitors : count(distinct visitor)
but how can i get accumulation distinct visitor count???
Thanks to every body..

Answer 1

SQL> select dt,cnt,sum(cnt1) over(order by dt) cnt1
  2  from(
  3  select dt,count(distinct visitor) cnt,sum(flg) cnt1
  4  from
  5   (select dt,visitor,(select decode(count(*),0,1,0)
  6                           from test
  7                           where rowid < t.rowid
  8                           and visitor = t.visitor) flg
  9   from test t)
10  group by dt);
DT                CNT       CNT1
10-01               3          3
10-02               3          4
10-03               3          5
10-04               2          5
Message was edited by:
        jeneesh
Wrong...