>>Try using derived table - it will be most likely a better performance:
>>

>>select M.FirstName, M.LastName, O.AddDate, O.CountRecord from Member M
>>inner join (select max(AddDate) as AddDate, count(*) as CountRecord, NoMember 
>>from [Order] group by NoMember) O
>>on M.Numero = O.NoMember

>
>Do you see a difference with Hugo's approach in regards to performance?

Both suggestions are exactly the same (but I was quicker :))
If you need to get records with no orders, change INNER JOIN to LEFT JOIN.