Re: Fixing row comparison semantics

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
Cc: pgsql-hackers@postgresql.org
Date: 2005-12-24T14:53:05Z
Lists: pgsql-hackers
Christopher Kings-Lynne <chriskl@familyhealth.com.au> writes:
> Can someone explain to me how:
> (a, b) < (1, 2)
> is different to
> a < 1 and b < 2

Right at the moment our code interprets it that way, but this behavior
is wrong per spec.  It should be an ordered column-by-column comparison,
so that the equivalent simple expression is

	(a < 1) OR (a = 1 AND b < 2)

			regards, tom lane