Re: Oracle 7.1 Enhancements

In article <2ttklb$kso_at_u.cc.utah.edu> mem8321_at_u.cc.utah.edu (Mark Miller) writes:
>In my opinion the SQL treatment of NULLS has a few serious flaws.
>
> NULL should be treated like an empty set in set algebra.
>
> e.g. ( column <> B ) should be true if column is NULL.
>
> Otherwise NOT ( column <> B ) does not equal ( column = B ).
>
> NULL should behave like a value that is equal to nothing and
> unequal to everything.
>
> I welcome your comments.

I see your point; however, let's look at the example of employees receiving a commission (This comes from Oracle SCOTT/TIGER examples)

Let say we have a table as such:

EMPLOYEES

employee_nb     number(5)
week-ending     date
salary_am       number(8,2)

(I will concede my table is not normalized, but I think the point is  still valid)

Let us assume that if you are not in sales you do not have a commission. Your commission is not zero, but rather null.

Let us say we want a list of employees whose commission for the week is over $400, and another list of employees whose commision is less than or equal to $400. Since commission is an illogical or not applicable concept for non-sales people, people who aren't sales people should logically not appear in either list. And, as I understand it, by the rules of ANSI SQL, they would not.

To address your original dilemma:

One could always use a SQL clause like

       where not nvl(column,'A') <> 'B'

which would be that same as

        where nvl(column,'A') = 'B'

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Michael Sallwasser  | Down one path is utter dispair and hopelessness. Down 
Northrop Grumman    | the other is total destruction. Let us choose wisely.
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