Posted by Dan Guzman on 12/10/06 13:24

To add to Erland's response, an index with leaf nodes that contain all
columns needed by a query is a 'covering' index. Besides the clustered
index key columns, one can add non -key columns in a SQL 2005 non-clustered
by specifying an INCLUDE column list in order to cover particular queries.

--
Hope this helps.

Dan Guzman
SQL Server MVP

"serge" <sergea@nospam.ehmail.com> wrote in message
news:9nNeh.60443$4A.1105486@wagner.videotron.net...
> If you display the execution plan and run the following:
>
> SET STATISTICS IO ON
> go
>
> SELECT ProductID, SupplierID
> FROM Products
> WHERE SupplierID = 1
>
>
> I don't understand how come there is no
> Bookmark Lookup operation happening to get the
> ProductID?
>
> I only see an Index Seek happening on SupplierID.
> There is no composite index SupplierID + ProductID
> so what am I not understanding here?
>
> Thank you
>
>

[Back to original message]