Re: Examples of SQL anomalies?
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 04 Jul 2008 16:29:36 -0300
Message-ID: <486e7a25$0$4054$9a566e8b_at_news.aliant.net>
>>David Cressey wrote:
>>
>>>"Brian Selzer" <brian_at_selzer-software.com> wrote in message
>>>news:nFD9k.5753$LG4.2422_at_nlpi065.nbdc.sbc.com...
>>>
>>>
>>>>"-CELKO-" <jcelko212_at_earthlink.net> wrote in message
>>
>>>news:f219a6bd-9d8e-4cfe-9d60-ce9dcaeff16d_at_z66g2000hsc.googlegroups.com...
>>>
>>>>>>>The question is, if these issues are due to the SQL specification or
>>>>>>>simply due to a problem in a specific SQL product. Or could it be, that
>>>>>>>the definition is not precise enough in some points, so that database
>>>>>>>vendors implemented it differently? <<
>>>>>
>>>>>Nope, it is the specs. All aggregate (set) functions begin by
>>>>>removing the NULLs from their parameter set, then if there is a
>>>>>DISTINCT option on the parameter, they remove redundant duplicates and
>>>>>finally do the operation (MIN, MAX, AVG, SUM, COUNT on what is left.
>>>>>Since an empty set has no elements upon which to apply an operation,
>>>>>SQL returns a NULL (okay, it should be an "undefined" if we were
>>>>>mathematically correct).
>>>>
>>>>MIN, MAX and AVG are meaningless when applied to an empty bag, but it seems
>>Bullshit! The identity element for min is the largest representable
>>value. The identity element for max is the smallest representable element.
Date: Fri, 04 Jul 2008 16:29:36 -0300
Message-ID: <486e7a25$0$4054$9a566e8b_at_news.aliant.net>
David Cressey wrote:
> "Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message > news:486ce002$0$4032$9a566e8b_at_news.aliant.net... >
>>David Cressey wrote:
>>
>>>"Brian Selzer" <brian_at_selzer-software.com> wrote in message
>>>news:nFD9k.5753$LG4.2422_at_nlpi065.nbdc.sbc.com...
>>>
>>>
>>>>"-CELKO-" <jcelko212_at_earthlink.net> wrote in message
>>
>>>news:f219a6bd-9d8e-4cfe-9d60-ce9dcaeff16d_at_z66g2000hsc.googlegroups.com...
>>>
>>>>>>>The question is, if these issues are due to the SQL specification or
>>>>>>>simply due to a problem in a specific SQL product. Or could it be, that
>>>>>>>the definition is not precise enough in some points, so that database
>>>>>>>vendors implemented it differently? <<
>>>>>
>>>>>Nope, it is the specs. All aggregate (set) functions begin by
>>>>>removing the NULLs from their parameter set, then if there is a
>>>>>DISTINCT option on the parameter, they remove redundant duplicates and
>>>>>finally do the operation (MIN, MAX, AVG, SUM, COUNT on what is left.
>>>>>Since an empty set has no elements upon which to apply an operation,
>>>>>SQL returns a NULL (okay, it should be an "undefined" if we were
>>>>>mathematically correct).
>>>>
>>>>MIN, MAX and AVG are meaningless when applied to an empty bag, but it seems
>
>>Bullshit! The identity element for min is the largest representable
>>value. The identity element for max is the smallest representable element.
> > Unless I'm mistaken, you're attributing to me something written by Brian. > I have trouble enough taking responsibility for my onw BS. I don't need to > have other people's BS charged against me!
You are mistaken. One needs to count the chevrons.
This is the risk one runs when one responds to nonsense without calling out the nonsense. Received on Fri Jul 04 2008 - 21:29:36 CEST