ค่าก่อนหน้าและค่าถัดไป

SELECT TerritoryName, OrderDate, 
       -- Specify the previous OrderDate in the window
       ___(OrderDate) 
       -- Over the window, partition by territory & order by order date
       ___(___ BY ___ ___ BY ___) AS PreviousOrder,
       -- Specify the next OrderDate in the window
       ___(OrderDate) 
       -- Create the partitions and arrange the rows
       ___ AS NextOrder
FROM Orders