Re: Select Distinct (was top N or rewriting MAX)

In article <32DEC3C1.7393_at_rci.rogers.com>, AWILSON <awilson_at_rci.rogers.com> writes
>Pardon my jumping in again,
>
>This raises a couple of interesting points.
>
>How does Select Distinct work - ie what mechanism does it use to ensure
>distinctness?

It sorts the results and then does a table scan of the sorted set returning distinct rows. It may be able to use an index to achieve the same result, but in either case the ordering of the result is an accident.

>Can it be relied upon to work the same way in future?
>

The safe answer is no, but I can't think of any mechanisms which would not result in a sorted set. Any clever computer science types out there who know of ways to achieve this?

-- 
Jim Smith