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: Amit Kapila <amit.kapila@huawei.com>, pgsql-hackers@postgresql.org
Date: 2012-08-06T15:09:09Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> I think you can always simulate CROSS APPLY using LATERAL.  The syntax
> is different but the functionality is the same.  However, OUTER APPLY
> allows you to do something that I don't think is possible using
> LATERAL.

Uh, what exactly?  AFAICT from that blog entry, "x OUTER APPLY y" is
exactly the same as "x LEFT JOIN LATERAL y ON true".  Okay, so you
saved three words, but is that a good enough reason to invent a
nonstandard syntax?

			regards, tom lane