Thanks, I now see why. :)

--- In firebird-support@yahoogroups.com, Jonathan Neve
<jonathan@m...> wrote:

>
> Glebas wrote:
>
> >Hello,
> >
> >Using FB1.52 on Windows:
> >
> >select tbl.fld as alias from tbl where alias is null
> >
> >complains about 'alias' in 'where' clause:
> >'Column does not belong to referenced table'
> >
> >
> FB 1.5.2 doesn't support using aliases in the where clause.
>
> >in firebird 2 release notes I found that now field aliases can be

used

> >in 'order by' and 'group by'. But why 'where' clause is so

special?

> >
> >
> I agree, it would be nice. Perhaps in a future version.
>
> I suggested that once, but I was told that it would be difficult

because

> (IIRC) the where clause is evaluated before the fields in the

select.

>
> --
> Best regards,
> Jonathan Neve
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