Subject Re: Re: [firebird-support] Is there any logical difference?
Author Svein Erling Tysvær
Post date 2019-08-12T08:55:06Z
I certainly agree with you that if EXISTS returns false, then NOT EXISTS should return true. It could make some sense if both EXISTS and NOT EXISTS returned <null> (though it should be documented somewhere), but not that one returns false and the other <null>. When you write this in the tracker, I think it would be good if you included a very simple reproducible test case.

Set

man. 12. aug. 2019 kl. 10:01 skrev liviuslivius liviuslivius@... [firebird-support] <firebird-support@yahoogroups.com>:


 
>>Thank you Set for the help. I must do one more test on monday. I must modify Case to comparision
>>CASE WHEN EXISTS() IS NULL THEN -1 ...
>>And we will see if exists can return something else then TRUE or FALSE
 
i have tested it now and i suppose result is wrong
 
------------------------------------
 
SELECT
EXISTS() return False
FROM
WHERE
...
 
------------------------------------
 
but
SELECT
NOT EXISTS() return NULL!!! instead of True
FROM
WHERE
 
------------------------------------
 
i suppose it is an error and should be reported to the tracker?
 
 
Regards,
Karol Bieniaszewski