Re: order of clauses

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От Steve Wolfe
Тема Re: order of clauses
Дата
Msg-id 00b701c09854$7c76a900$50824e40@iboats.com
обсуждение исходный текст
Ответ на order of clauses  (Patrick Welche <prlw1@newn.cam.ac.uk>)
Список pgsql-general
> > will give a divide by zero error as A=(y>0) and B=(x/y>1) can be
evaluated in
> > any order (A and B = B and A). I obviously would like (y>0) to happen
first,
> > but I don't see how this can be achieved.. Any ideas?

  I have one idea that would be nifty to implement.  In some compilers, you
can turn off complete boolean checking.  As soon as any part of an
expression will invalidate the expression, it stops evaluating all of it.
That can help you avoid division by zero, and keeps you from evaluating
parts of the expression that don't matter.  It sounds like a good idea, at
least to an ignoramus like me. : )

steve



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