> On Fri, 02 Mar 2012 09:03:02 +0100, Mark Rotteveel<mark@...>
> wrote:
>> On Tue, 28 Feb 2012 07:37:59 -0000, "syn.erpy"<syn.erpy@...>
> wrote:
>>> Hi,
>>>
>>> we ran into a little problem regarding blanks.
>>>
>>> Try the following code (FB 2.5.1):
>>>
>>> <code>
>>> create exception blank 'blank';
>>>
>>> SET TERM ^ ;
>>>
>>> create OR alter procedure p_test
>>> as
>>> begin
>>>
>>> IF (' ' = '') THEN
>>> exception blank;
>>> end
>>> ^
>>>
>>> SET TERM ; ^
>>>
>>> execute procedure p_test;
>>>
>>>
>>> </code>
>>>
>>> If you run it, the exception is raised. My question is why Firebird
>> thinks
>>> that a blank (or two or three or four for that matter) is the same as
> an
>>> empty string. Is this a bug or an intended feature?
>>
>> Because that is what the SQL standard defines: When comparing strings
> the
>> shorter string is padded with spaces to the length of the longer string,
>> and then they are compared. So if two strings have the same prefix and
> the
>> rest is a (different) number of spaces, then they are still considered
> the
>> same.
>
> I am not 100% sure (and no Firebird installation at hand to check), but I
> believe ' ' IS DISTINCT FROM '' should work.

It doesn't.

select 1 from rdb$database where '' is distinct from ' '

gives an empty result set.

Where as:

select 1 from rdb$database where '' is not distinct from ' '

does.

Tested with Firebird 2.5.0.


--
With regards,
Thomas Steinmaurer (^TS^)
Firebird Technology Evangelist

http://www.upscene.com/

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