On Thu, Nov 01, 2007 at 02:22:58PM -0400, Tom Lane wrote:
> > SELECT random() FROM generate_series(1, 10) ORDER BY random();
> > SELECT random() AS foo FROM generate_series(1, 10) ORDER BY foo;
>
> (BTW, this is not the planner's fault; the collapsing of the two
> targetlist entries into one happens in the parser.)
Something twigged telling me that in fact the latter expression is not
in standard SQL but a (very common) extension. A <sort key> is clearly
indicated to be a <value expression> with no indication anywhere that
column aliases are allowed here (though that may be in the common rules
somewhere).
Then again, I may be remembering all wrong...
Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> Those who make peaceful revolution impossible will make violent revolution inevitable.
> -- John F Kennedy
