SUM of only TOP 10 rows

Question

I have a query where I am only selecting the TOP 10 rows, but I have a SUM function in there that is still taking the sum of all the rows (disregarding the TOP 10). How do I get

Answer 1

Use the TOP feature with a nested query

SELECT SUM(innerTable.Purchase_Total_Amount) FROM
(SELECT TOP 10 Purchase_Total_Amount FROM Table) as innerTable

Answer 2

Have you tried to use something like this:

SELECT SUM(Whatever)
FROM (
    SELECT TOP(10) Whatever
    FROM TableName
) AS T