> By selecting the last 200 on some identifiable criteria and not
> selecting 999,800 records you don't want.

ok, if the user want simply the last 200 inserted record of a table that have 100 000 records, how you do without index on the ordering clause ?

> Even if your result set is large, you'll finish the whole operation
> faster by selecting and sorting. Retrieving records in index order
> is faster if you care only about the time to get the first record.

yes, that i say, i you want only the First xxx reccord, not all the set of course ! in this way is mostly better to use the index on the ordering clause ...