Helen, I've just run the same test on my home computer (win xp), and
substr works fine. The problem may be specific to my work
computer. I will
investigate some more.

Thanks,

Binh

--- In firebird-support@yahoogroups.com, Helen Borrie <helebor@t...>
wrote:

> At 02:07 PM 19/12/2003 -0800, you wrote:
> >Background: FB 1.5 RC6, Windows 2000.
> >
> >I have table news where txt is a column defined as
> >varchar(255).
> >
> >When issuing the SQL:
> >select substr(txt,1,2) from news;
> >
> >
> >Then, I get the mentioned error. I am certain that
> >all txt rows contains enough text (20 characters or
> >more).
>
> Is the example the way you are actually calling the UDF? The

exception

> you report shouldn't (couldn't) occur with this statement.
>
> fwiw, I've just run your statement on several samples, including a

unicode

> column that has null on several rows, without exception.
>
> Firebird has an internal function SUBSTRING() which avoids the

UDF, btw.

>
> select substring(txt FROM 1 FOR 2) as outputcol from news;
>
> /heLen