Re: [Firebird-devel] SUBSTRING Function

[Andrea C. P. <ac...@bi...>]

Hi,

Claudio,

> Do you mean subftest1 || subftest2, right? We don't support the "+", the
> ANSI operator is "||".

sorry, you are right. I use "+" only in my frontend application
(VisulFoxPro). In SQL I use "||"

Dimitry,

>I don't think that the type of SUBSTRING() result may be changed in
>the future versions of FB. At first, it would make problems with
>compatibility. Second, some other people (including me) would like
>the result to be an VARCHAR because they don't need trailing blanks.

Ok. I dont think VARCHAR is the real problem. Varchar is also ok for me but

if field is char(30) or varchar(30)

and I write substring as SUBSTRING(field FROM 1 FOR 5)

it returns VARCHAR(30)

and not VARCHAR(5) since we know len of return string we want with FOR
clause?

Thank you

--
Andrea Chiadò Piat
Bit Informatica s.r.l.
Progettazione e Sviluppo

""Claudio Valderrama C."" <cv...@us...> ha scritto nel messaggio
news:NBB...@us......
> > -----Original Message-----
> > From: fir...@li...
> > [mailto:fir...@li...]On Behalf Of Andrea
> > Chiado' Piat
> > Sent: Lunes 29 de Julio de 2002 13:56
> >
> > and it is right but fields subftest1 and subftest2 are 10 char lenght so
> > when in my application I do subftest1+subftest2
>
> Do you mean subftest1 || subftest2, right? We don't support the "+", the
> ANSI operator is "||".
>
>
> > I have
> >
> > 01          23
> > and not 0123
> >
> > Probably results fields are initialized as varchar(field lenght) and
then
> > filled with a null terminated string.
>
> No. But this is problem that comes from the time the function was done
> originally. It was an ASCII thing, not able to tackle international
charsets
> at all. It was used for internal tasks only. But in general terms,
substring
> seems to work okay. The problem is concatenation: it currently doesn't
> follow the ANSI-SQL specification that has detailed rules to mix char and
> varchar.
>
>
> > It is not possible inizialize field as CHAR(len of FOR clause) in new
> > firebird versions since we know the lenght we want return string?
>
> I don't think your suggestion applies at all. We only know there's a
> divergence WRT the standard. Either substring and/or concatenation should
be
> polished.
>
>
> > All database I worked with (DB2, ORACLE, SQL) returns exact
> > lenght so I have
> > a lot of applications to convert to firebird but a lot of line of code
to
> > adjust
>
> If I remember well, char will always produce that effect, so the correct
> case to fix is when varchars are involved.
>
> C.
>
>
>
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