mrdenny
46810 pts. | Jan 21 2009 7:36PM GMT
Searches against a clustered index are not quicker than against a nonclustered index.
Searches against a nonclustered index will appear slower is the clustered index isn’t build correctly, or it does not include all the columns needed to return the data back to the calling application. In the event that the non-clustered index doesn’t contain all the needed data then the SQL Server will go to the clustered index to get the missing data (via a lookup) which will make the query run slower as the lookup is done row by row.






