Re: Range Type constructors

On Wed, Feb 9, 2011 at 2:09 AM, Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
> That's how arrays do it: there's a special Expr node that represents an
> array expression. Maybe the same thing could be used for range types,
> but I fear that there may be some grammar conflicts. I doubt we'd want
> to fully reserve the keyword "range".

According to our documentation[1], RANGE is reserved in SQL:2008 and
SQL:2003, which makes it more imaginable to reserve it than it would
be otherwise. I believe that in a previous email you mentioned that
you were hoping to implement RANGE JOIN, and I will just note that the
restrictions of the grammar require that any keyword that immediately
follows the previous expression and precedes JOIN must be fully
reserved. I'm not sure if you meant that a range join would literally
use the syntax RANGE JOIN, but if so then you're going to have to
argue for fully reserving RANGE anyway, in which case there'd be no
special reason not to allow RANGE [1,10) to mean just that. On the
other hand, if a RANGE JOIN just means a regular join on some funky
operator, and there's no other reason to reserve range, I wouldn't do
it just to get a nicer syntax here.

Have you done investigation of what RANGE is used to mean in the SQL
spec? Is what you're implementing (a) spec, (b) similar idea, but not
the spec, or (c) something completely different? I'm guessing (c) but
I have no idea what the spec is using it for.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

[1] http://www.postgresql.org/docs/current/static/sql-keywords-appendix.html