You generate a daily report according to the following query:

You need to improve the performance of the query.

What should you do?

A. Drop the UDF and rewrite the report query as follows:

SELECT c.CustomerName

FROM Sales.Customer c

WHERE NOT EXISTS (

SELECT s.OrderDate

FROM Sales.SalesOrder s

WHERE s.OrderDate > DATEADD(DAY, -90, GETDATE())

AND s.customerID = c.CustomerID)

B. Rewrite the report query as follows:

SELECT c.CustomerName

FROM Sales.Customer c

WHERE (SELECT OrderDate FROM Sales.ufnGeTLastOrderDate(c.CustomerID)) < DATEADD(DAY, -90, GETDATE())

Rewrite the UDF as follows:

CREATE FUNCTION Sales.ufnGeTLastOrderDate(@CustomerID int)

RETURNS @OrderTable TABLE (Order

Date datetime)

AS

BEGIN

INSET @OrderTable

SELECT MAX(s.OrderDate) As OrderDate

FROM Sales.SalesOrder s

WHERE s.CustomerID = @CustomerID

RETURN

END

C. Rewrite the report query as follows:

SELECT c.CustomerName

FROM Sales.Customer c

WHERE NOT EXISTS

(SELECT OrderDate FROM Sales.ufnGetRecentOrders(c.CustomerID, 90))

Rewrite the UDF as follows:

CREATE FUNCTION Sales.ufnGetRecentOrders(@CustomerID int, @MaxAge datetime)

RETURNS TABLE AS RETURN (

SELECT OrderDate

FROM Sales.SalesOrder s

WHERE s.CustomerI

D = @CustomerID

AND s.OrderDate > DATEADD(DAY, -@MaxAge, GETDATE()))

D.Drop the UDF and rewrite the report query as follows:

SELECT c.CustomerName

FROM Sales.Customer c

INNER JOIN Sales.SalesOrder s ON c.CustomerID = s.CustomerID

GROUP BY c.CustomerID

HAVING MAX (s.OrderDate) < DATEADD(DAY, -90, GETDATE())

Explanation: