Queries :: Distinct Count In Subquery

Extended Cost] and salestran.[Extended Price] for each salestran.[SKU Code/Number], Count the number of unique customers, salestran.[Customer Code/Number], per SKU for any transactions equal to or after salestran.[Transaction Date] 11/1/2014.

Problem is, doing a regular count on the Customer field returns an incorrect value. It counts the number of times the sku appears within the given date range, ie 6 transactions with 2 customers, my count says 6. I need a distinct count on the customer, for the above example I want to see 2. Here is the code I have so far which yields an error of "At most one record can be returned.." distinct count in my Select statement along with the other fields I want to see, ie Summary data and SKU.

SELECT Salestran.[SKU Code/Number], (SELECT COUNT(cd.[Customer Code/Number]) AS Count FROM (SELECT Distinct [SKU Code/Number], [Customer Code/Number] FROM Salestran) as cd GROUP BY cd.[SKU Code/Number]) AS [Number of Customers]
FROM Salestran
WHERE (((Salestran.[Transaction Date])>=#11/1/2014#))
GROUP BY Salestran.[SKU Code/Number];