Re: Fixing row comparison semantics

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Fixing row comparison semantics
Date: 2005-12-24 14:53:05
Message-ID: 14907.1135435985@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)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

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Greg Stark 2005-12-24 15:16:52 Re: [Bizgres-general] WAL bypass for INSERT, UPDATE and
Previous Message Tom Lane 2005-12-24 14:45:30 Re: Fixing row comparison semantics