From: jurka at ejurka.com (Kris Jurka)
Date: Mon, 26 Dec 2011 20:02:48 -0800
Subject: [Pljava-dev] testing for equality in user-defined types in
 select statements
In-Reply-To: 
 <CALBNtw6S9hkouW=m-quHw_TZD=SQi-NJKE+NCKkHOS3wh1O_1w@mail.gmail.com>
References: 
 <CALBNtw6S9hkouW=m-quHw_TZD=SQi-NJKE+NCKkHOS3wh1O_1w@mail.gmail.com>
Message-ID: <4EF94368.8020200@ejurka.com>

On 12/26/2011 7:41 PM, Bear Giles wrote:
> I have a UDT for rational numbers.  I want to be able to add it in
> select statements but it doesn't work.
> >
>     select f.value, f.foo, b.bar from foo f join bar b on (f.value =
> b.value);
>
> I vaguely recall that there were standard function names for this when I
> played with C UDT years ago but that was PSQL version 5.x or 6.x. Is
> that still the case? In either case the wiki should be updated.
>

You are looking for CREATE OPERATOR for equality/comparison and CREATE
OPERATOR CLASS for ordering definition.  These are no different for 
pljava types vs any other implemented type.

Kris Jurka