Re: Examples of SQL anomalies?

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Wed, 02 Jul 2008 10:12:55 -0300
Message-ID: <486b7edb$0$4070$9a566e8b@news.aliant.net>


Bob Badour wrote:

> David Cressey wrote:
> 

>> "Gene Wirchenko" <genew_at_ocis.net> wrote in message
>> news:foma64l9qgshnt7pdopcu9b53i9atpcp4p_at_4ax.com...
>>
>>> -CELKO- <jcelko212_at_earthlink.net> wrote:
>>>
>>>
>>>>>> I do not use nulls in my tables. I still get null when I sum what
>>
>>
>> turns out to be zero rows. If I want the total amount charged on
>> invoices
>> for a client in a certain date range, and there are no such invoices, the
>> total is zero. <<
>>
>>>> No, that is flat wrong. There is no such invoice, so the question of
>>>> its total makes no sense. It is a totally different kind of thing
>>>
>>>
>>>> from an invoice that actually totaled to zero. Zero, empty set, empty
>>>
>>>
>>>> strings, NULLs, etc. are all different concepts around the idea of
>>>> missing data of some kind.
>>>
>>>
>>> If I want the total amount invoiced in a time period and there
>>> are no invoices, the total amount invoiced was zero.
>>>
>>>
>>>> Also, why are you using cursors? If you want to give this misleading
>>>> data, then use a COALESCE(invoice_tot, 0.00) in your code.
>>>
>>>
>>> Null is the misleading datum.
>>
>>
>> Except that null isn't a datum. If you consider it a datum, that may
>> be why
>> you are misled.
> 
> 
> Except that the total invoiced is a datum, and he requested that datum, 
> which has no reason or excuse for NULL.

Correction: no legitimate excuse. Received on Wed Jul 02 2008 - 08:12:55 CDT

Original text of this message