Subject Re: [firebird-support] Re: Why NULL <> NULL ?
Author Kjell Rilbe
jasajona wrote:

> --- In, Lucas Franzen <luc@...> wrote:
>>So your conclusion is that we both have the same amount of money in
>>our wallets, since we both have NULL....
> How do you know that we have not equal amount? :)

You don't know either way, and that's exactly why the comparison
evaluates to null (unknown). It makes a lot of sense.

> In this case
> exception would be logical way to react to such situation.

No, that wouldn't be useful at all, because you'd have to handle LOADS
of exceptions EVERYWHERE in close to ALL databases IN THE WHOLE WORLD.

> False - is
> also answer, I had to swap statements of "then" and "else".

Think of it this way: if you ask for records that fulfil a certain
condition, you want to get those records that you KNOW fulfil the
condition. You certainly don't want those that you KNOW DON'T. THose
records you don't know either way, you'd better make sure you know, for
example by using coalesce, or you'd better not get them, because you
wouldn't know what you get.

Kjell Rilbe
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E-post: kjell.rilbe@...
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