Re: WIP patch for LATERAL subqueries

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org
Date: 2012-08-06T14:47:53Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> Apparently Sybase and Microsoft SQL server use a slightly different
> syntax, CROSS APPLY, for this.

> http://iablog.sybase.com/paulley/2008/07/cross-and-outer-apply/

Well, this is only a blog entry and not their manual, but AFAICT that is
just a useless deviation from SQL-standard syntax; it does nothing that
"CROSS JOIN LATERAL" or "LEFT JOIN LATERAL ... ON true" wouldn't do.
I can't tell if the blogger simply doesn't know that LATERAL can be used
in a JOIN nest, or if that's actually a misfeature of the DBMS.

I'm not in favor of duplicating this.

			regards, tom lane