As I have just read this part of articles. A question arise in my mind :-D about figure 5. As my I understanding after reading untill part 9 is:
with query below
SELECT C.LastName, C.FirstName, C.MiddleName, C.Title, H.SalesOrderID, H.OrderDate
FROM Person.Contact C
JOIN Sales.SalesOrderHeader H ON H.ContactID = C.ContactID
WHERE Suffix is null
ORDER BY Title
I think the query plan should be still
like figure 4 (not changing). This is because index IX_ContactID which added later does not give more advantage (lack field SalesOrderID to show for final output). How come with new index IX_ContactID and Clustered Index of table Contact, we can produce field SalesOrderID for final result?
Please give me enlightenment here :-).