order by question

Hi,
I wonder if following result set would be sorted according to x.z. Or is it possible that the optimizer for some reason, based on the outer conditions, decides to get the result unsorted because it would be more performant.

select sub.*
  from (select x from y order by x.z) sub

 where ...
    and ...
    and ...

If this works the (select x from y order by x.z ) would be a view.

I have not been able to get a resultset which is unsorted acording to x.z but need to know that this would not happen in a productive environment.

With regards
Slavko Received on Thu Oct 23 2008 - 09:34:51 CDT