Try with this:
SELECT A.personId, A.LogDate, A.selectedValue
FROM MySelectedValues AS A
INNER JOIN (
SELECT personId, MAX(logDate) AS LogDate
FROM MySelectedValues
GROUP BY personId
) AS B
ON A.personId = B.personId
AND A.LogDate = B.LogDate
Regards
Gianluca
-- Gianluca Sartori