PIVOTとJOINを一緒に使用する

WITH T
     AS (SELECT [Order Details].OrderID,
                c.CategoryName,
                c.CategoryID
         FROM   [Order Details]
                INNER JOIN Products p
                  ON p.ProductID = [Order Details].ProductID
                INNER JOIN Categories c
                  ON c.CategoryID = p.CategoryID)
SELECT *
FROM   T PIVOT ( COUNT (CategoryID) FOR CategoryName IN ( 
       [Beverages],
       [Condiments],
       [Confections], 
       [Dairy Products], 
       [Grains/Cereals],
       [Meat/Poultry],
       [Produce],
       [Seafood]) ) AS pvt
ORDER  BY OrderID