Problem counter

Question

I have a chart with N record, a field it date, time, and a field number, has to insert in the field number a daily sequential counter...
ES:
TABLE PIPPO
DATE TIME CONT
01/01/2005     00:00          1
01/01/2005     01:00          2
02/01/2005     00:00          1
02/01/2005     00:30          2
03/01/2005     10:00          1
03/01/2005 10:05          2
....

Answer 1

Does this work for you ?
SQL> select * from t order by 1;
DATE#                      SEQ
25-07-2005 01:00:00
25-07-2005 02:00:00
25-07-2005 03:00:00
26-07-2005 01:00:00
26-07-2005 02:00:00
26-07-2005 03:00:00
26-07-2005 04:00:00
26-07-2005 05:00:00
26-07-2005 06:00:00
26-07-2005 07:00:00
27-07-2005 01:00:00
27-07-2005 02:00:00
27-07-2005 03:00:00
27-07-2005 04:00:00
27-07-2005 05:00:00
15 rows selected.
SQL> merge into t
  2  using (
  3  select rowid rwn,
  4  row_number() over(partition by trunc(date#) order by date#) rn
  5  from t) t1
  6  on (t.rowid = t1.rowid)
  7  when matched then
  8   update set t.seq = t1.rn
  9  when not matched then
10   insert (date#, seq) values (sysdate,0);
15 rows merged.
SQL> select * from t order by 1;
DATE#                      SEQ
25-07-2005 01:00:00          1
25-07-2005 02:00:00          2
25-07-2005 03:00:00          3
26-07-2005 01:00:00          1
26-07-2005 02:00:00          2
26-07-2005 03:00:00          3
26-07-2005 04:00:00          4
26-07-2005 05:00:00          5
26-07-2005 06:00:00          6
26-07-2005 07:00:00          7
27-07-2005 01:00:00          1
27-07-2005 02:00:00          2
27-07-2005 03:00:00          3
27-07-2005 04:00:00          4
27-07-2005 05:00:00          5
15 rows selected.Rgds.