On Wed, Dec 21, 2011 at 15:24, salah jubeh <s_jubeh@yahoo.com> wrote:
> Why I can not use it directly as shown in the example below.
> why a and b can not be used as aliases for the column names ? I want to know
> the theoretical reason behind it?
As far as I know, that's how the SQL standard specifies it. PostgreSQL
is pretty strict about following the SQL standard. Diverging from the
standard in this aspect would cause ambiguities.
Regards,
Marti