Obtaining the last n values - possible to do non-procedurally?

Question

I'm not sure if the following is possible without using PL/SQL instead garden variety SQL.
I'm looking for the last 4 or less (or some other arbitrary number) of LABVALUES for a PERSON. This is regardless of the time period in which they occur. Eventually I might AVERAGE these or do some other summary operation. The LABDATE might be a standard Oracle date, or might be a number (number of microseconds from 1/1/1960); however, these date forms would NOT be mixed in the same query.
The base query is:
SELECT DISTINCT
PERSON.NAME,
LAB.VALUE,
LAB.DATE
FROM
PERSON,
LAB
WHERE
PERSON.ID = LAB.ID
Does this have to be done procedurally or can it just be done as a SELECT statement
Thanks,
Will

Answer 1

Eric, Everything looks good assuming that we can go by Person.Id for order by clause, just couple of things,
1. William's spec does not have Person_Id column.
2. William also says he needs last 'n' rows for each Person, however he did not mention whether he passes 'Name' of the Person as a parameter. Following are couple of SQLs, one with Person Name as parameter and another one with out the parameter which brings all the persons with 'n' number of rows for each person.
/* Please note that I have not used analytical fn here, only because we can get away with out having to use it. Just an alternative ONLY. */
SELECT Name, Value, Date
FROM
   (Select P.Id
          , P.Name
          , L.Value
          , L.Date
    From PERSON P, LAB L
    Where P.Id = L.Id
    Group By P.Id, P.Name, L.Value, L.Date
    Order By P.Id Desc)
WHERE Name = :PersonName -- use Name of Person here as parameter
AND ROWNUM <= :n; -- number of rows required for the given Person
/* Please note that I have not used the group by here as PARTITION
does that for us*/
SELECT Name, Value, Date
FROM
   (Select  P.Name
          , L.Value
          , L.Date
          , row_number() over(PARTITION BY P.Name ORDER BY L.Id desc) Rn
   From PERSON P, LAB L
   Where P.Id = L.Id)
WHERE Rn <= :n; -- number of rows for each personThx,
SriDHAR