Dynamic Pivot Table Syntax Error

I am getting the error message - Msg 102, Level 15, State 1, Line 5 Incorrect syntax near ','. when I run the below query. I can't figure out why the syntax is incorrect. Does anyone have any suggestions?

DECLARE @Vendor AS INT = 41

CREATE TABLE #PivotData
(
    [ID] INT,
[Row] VARCHAR(MAX),
[Columns] VARCHAR(MAX),
[AggData] INT
)

INSERT INTO #PivotData

SELECT  V.Vendor_Key
    ,O.Location_Desc 
    ,P.Item_Desc
    ,IIF.Sales_Qty
FROM    PDI.PDI_Warehouse_952_01.dbo.Item_Inventory_Fact IIF
    INNER JOIN  PDI.PDI_Warehouse_952_01.dbo.Item_Purchases_Fact IPF
    ON IIF.Calendar_Key = IPF.Calendar_Key
    AND IIF.Organization_Key = IPF.Organization_Key
    AND IIF.Product_Key = IPF.Product_Key
INNER JOIN  PDI.PDI_Warehouse_952_01.dbo.Organization O
    ON IIF.Organization_Key = O.Organization_Key
INNER JOIN  PDI.PDI_Warehouse_952_01.dbo.Product P
    ON IIF.Product_Key = P.Product_Key
INNER JOIN PDI.PDI_Warehouse_952_01.dbo.Vendor V
    ON IPF.Vendor_Key = V.Vendor_Key
WHERE V.Vendor_key = @Vendor

DECLARE @Cols AS NVARCHAR(MAX),
    @Query AS NVARCHAR(MAX)

SET @Cols = STUFF ((SELECT DISTINCT ',' + QUOTENAME(P.Columns)
                FROM #PivotData P
                FOR XML PATH(''), TYPE
                ).value('.', 'NVARCHAR(MAX)')
                ,1,1,'')

 SET @Query = 'SELECT Row, ' + @Cols + ' FROM
            (
                SELECT  Row
                        ,Column
                        ,Aggregate
                FROM #PivotData
            )x
            PIVOT
            (
                SUM(Aggregate)
                FOR Row IN (' + @Cols + ')
            ) p '

EXECUTE(@Query)

DROP TABLE #PivotData