Update A Column with value of Column in the next Row

Question

Hi All,
I have a table which is like this
ID NUMBER,
SUB_ID NUMBER,
STARTDATE DATE.
The Value is say for example like this:
ID     SUB_ID     StartDate
1     1     1-JAN-09
1     2     20-FEB-09
1     3     1-MAR-09
2     1     10-JAN-09
2     4     10-APR-09
2     3     1-MAR-09
2     2     2-FEB-09
I have to add a new column END DATE in the table and populate a value which is One Day less than the value of
start Date for next row. I have to order by ID and SubID and so that colum looks like this.
ID     SUB_ID     StartDate          END DATE
1     1     1-JAN-09          19-FEB-09
1     2     20-FEB-09          28-FEB-09
1     3     1-MAR-09          DEFAULT-END DATE
2     1     10-JAN-09          1-FEB-09
2     2     2-FEB-09          8-Mar-09
2     3     9-MAR-09          9-APR-09     
2     4     10-APR-09          DEFAULT END DATE
Can this be achieved using a single update query or I have ot write a Procedure ...any help will be appreicaited

Answer 1

or
merge into test
using (select rowid rid
            , id
            , sub_id
            , startdate
            , lead (startdate) over (order by id, sub_id) - 1 ed
       from test) x
on (x.rid = test.rowid)
when matched then
   update set end_date = x.ed
;