Maintaining Indexes - Microsoft SQL Server 2012 Performance Tuning - page 244

POH.PurchaseOrderID
,POH.OrderDate
,EMP.LoginID
,V.Name AS VendorName
,SUM(POD.OrderQty) AS OrderQty
,SUM(POD.OrderQty*POD.UnitPrice) AS Amount
FROM
[Purchasing].[PurchaseOrderHeader] AS POH
JOIN
[Purchasing].[PurchaseOrderDetail] AS POD
ON
POH.PurchaseOrderID = POD.PurchaseOrderID
JOIN
[HumanResources].[Employee] AS EMP
ON
POH.EmployeeID=EMP.BusinessEntityID
JOIN
[Purchasing].[Vendor] AS V
ON
POH.VendorID=V.BusinessEntityID
GROUP BY
POH.PurchaseOrderID
,POH.OrderDate
,EMP.LoginID
,V.Name
GO

SELECT top 10 * FROM POView WITH (NOEXPAND)
GO

3. Now, if we review the execution plan, we can see that the execution plan of the

POView view is much better, due to the clustered index we have created on the view.
The first query searches records from the different indexes defined on the table that
comes with the AdventureWorks2012 database, whereas the second query on the
view searches records from the single clustered Index we have created on the view.