Re: Support for RANGE ... PRECEDING windows in OVER

On Sun, Jun 30, 2013 at 11:54 PM, ian link <ian@ilink.io> wrote:
> I found some time and I think I am up to speed now. I finally figured out
> how to add new operator strategies and made a little test operator for
> myself.
>
> It seems pretty clear that assuming '+' and '-' are addition and subtraction
> is a bad idea. I don't think it would be too tricky to add support for new
> operator strategies. Andrew Gierth suggested calling these new strategies
> "offset -" and "offset +", which I think describes it pretty well. I
> assigned the operator itself to be "@+" and "@-" but that can obviously be
> changed. If this sounds like a good path to you guys, I will go ahead and
> implement the operators for the appropriate types. Please let me know if I
> am misunderstanding something - I am still figuring stuff out :)

I don't think I understand the design you have in mind.  I'm actually
not clear that it would be all that bad to assume fixed operator
names, as we apparently do in a few places despite the existence of
operator classes.  But if that is bad, then I don't know how using @+
and @- instead helps anything.

-- 
Robert Haas
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