Re: NULL != text ?

On 10/20/2005 6:10 AM, Alban Hertroys wrote:

> Michael Glaesemann wrote:
>> if (OLD.value IS NOT NULL and NEW.value IS NOT NULL and OLD.value <>
>> NEW.value) or OLD.value IS NULL or NEW.value IS NULL
>>
>> But that's untested and I have a hard time thinking in three-value  logic.
>
> For completeness sake; Because of lazy evaluation, that boils down to:
>
> if (OLD.value IS NULL OR NEW.value IS NULL OR OLD.value <> NEW.value)

That would result in TRUE if both, OLD and NEW are NULL. Is that what
you intended?


Jan

>
> The last part of the expression is only evaluated if both OLD.value and
> NEW.value aren't NULL.
>


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