On Tue, May 14, 2002 at 01:35:47PM -0400, Edmund Dengler wrote:
>
> which flies as expected? Now, this type of thing gets me real worried
> about how good the optimizer really is.
The max() (and min()) operations are not rewritten, as you note.
There's no rule for it. There was a recent discussion about this --
check the archives.
There's a similar set of worries, apparently, for NOT EXISTS versus
NOT IN. In the vast majority of cases, it seems, NOT EXISTS is
considerably faster than NOT IN; but not in all cases. So the
queries are executed differently, and never get rewritten one to the
other. The only answer is to try to make sure your criteria-written
queries are generated in a way that is usually pretty good. For
sure, min() and max(), and NOT IN, and a couple of others (count()
comes to mind) are almost always losers, so you should avoid them.
A
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