Multiple max values in a query

I know the title does not sound very descriptive, but it is the best I could think of:

I have this table

ID     BDATE      VALUE
28911  14/4/2009  44820
28911  17/4/2009  32240
28911  20/4/2009  30550
28911  22/4/2009  4422587,5
28911  23/4/2009  4441659
28911  24/4/2009  7749594,67
38537  17/4/2009  58280
38537  20/4/2009  137240
38537  22/4/2009  81098692
38605  14/4/2009  2722368
38605  20/4/2009  5600
38605  22/4/2009  1625400
38605  23/4/2009  6936575

which is in fact a very complicated query encapsulated in a view, but it is not of the matter now.

I would like to have for each ID, the row containing the highest BDate. In this example, this would be the result.

ID     BDATE      VALUE
28911  24/4/2009  7749594,67
38537  22/4/2009  81098692
38605  23/4/2009  6936575

I have already tried

select id, max(bdate), value from myview group by id, value

but then it returns all the ro开发者_StackOverflow中文版ws, because for each the value collumn is different. This query is designed in Oracle v10, and I am eligible to use only select queries and not to create procedures.

We can use multiply columns in an IN clause:

select id, bdate, value 
from myview 
where (id, bdate) in
    (select id, max(bdate)
     from myview group by id)
/

you can use the MAX...KEEP(DENSE_RANK FIRST...) construct:

SQL> SELECT ID,
  2         MAX(bdate) bdate,
  3         MAX(VALUE) KEEP(DENSE_RANK FIRST ORDER BY bdate DESC) VALUE 
  4   FROM DATA
  5  GROUP BY ID;

        ID BDATE            VALUE
---------- ----------- ----------
     28911 24/04/2009  7749594,67
     38537 22/04/2009    81098692
     38605 23/04/2009     6936575

This will be as efficient as the analytics method suggested by Majkel (no self-join, a single pass on the data)

You can use an INNER JOIN to filter out only the maximum rows:

select t.*
from YourTable t
inner join (
     select id, max(bdate) as maxbdate
     from YourTable
     group by id
) filter
    on t.id = filter.id
    and t.bdate = filter.maxbdate

This prints:

id     bdate       value
38605  2009-04-23  6936575
38537  2009-04-22  81098692
28911  2009-04-24  7749594.67

Note that this will return multiple rows for an id which has multiple values with the same bdate.

You can use analytics:

select 
      id, bdate, value 
    from
      (
        select
          id, bdate, value, max( bdate ) over ( partition by id ) max_bdate
        from
          myview
      )
    where
      bdate = max_bdate

select a.* from myview a, (select id, max(bdate) from myview group by id) b
where a.id = b.id and a.bdate = b.bdate

SELECT id, bdate, value FROM myview
 WHERE (id, bdate) IN (SELECT id, MAX(bdate) FROM myview GROUP BY id)

(untested... I don't have Oracle available right now...)