RE: Request for clarification

The specs are being updated. Hopefully will be out shortely.

There is a newer ADQL spec in the Madrid IVOA meeting page.

Maria

On Tue, 29 Nov 2005, Tony Linde wrote:

> Sounds like the spec needs to be updated to make all these points clear.
>
> T.
>
> > -----Original Message-----
> > From: owner-voql-at-eso.org [mailto:owner-voql-at-eso.org] On
> > Behalf Of Yuji SHIRASAKI
> > Sent: 29 November 2005 07:34
> > To: kea-at-ast.cam.ac.uk
> > Cc: voql-at-ivoa.net
> > Subject: Re: Request for clarification
> >
> >
> > Hi Kona Andres,
> >
> > > Question 1 -
> > > I am inferring from the above that in *any* ADQL query, it is
> > > necessary to declare an alias for each and every table
> > referenced in
> > > that query - is that correct? In other words, the
> > unambiguous query
> > > "select ra,dec from mytable" is invalid ADQL because it
> > lacks an alias
> > > declaration for mytable?
> >
> > Yes, you must have table alias in ADQL.
> > "select ra, dec from mytable" should be "select ra, dec from
> > maytable t".
> >
> > > Question 2 -
> > > As I understand it, SQL uses the syntax "from table as t"
> > rather than
> > > "from table t" when declaring aliases. Am I incorrect here, or if
> > > not, should we be including the "as" keyword in our ADQL/s alias
> > > declarations?
> >
> > You may omit "as" keyword. So both "from table t" and "from
> > table as t"
> > are valid.
> >
> > > Question 3 -
> > > If it is compulsory to declare aliases for all tables, is it also
> > > compulsory to *use* table alias prefixes for all column
> > references in
> > > a query, even when they are otherwise unambiguous?
> >
> > No. You don't need to use the table alias prefix if it is unambiguous.
> >
> > ---
> > Yuji SHIRASAKI, Research Fellow +81-422-34-3579 (tel)
> > National Astronomical Observatory of Japan +81-422-34-3840 (fax)
> > Osawa, Mitaka, Tokyo, Japan
> > yuji.shirasaki-at-nao.ac.jp
> >
> >
> >
>

-- 
------------------------------------------------
Maria A. Nieto-Santisteban (nieto-at-pha.jhu.edu)
Johns Hopkins University
3400 N. Charles St.
Physics & Astronomy Department
Baltimore, MD 21218 (USA)

Tel: 	1 410 516-7679  Fax: 	1 410 516-5096