Re: Restriction of windows functions

On 17.06.2016 17:01, Tom Lane wrote:
>
> Certainly it assumes that window is ordered by key and the key type
> supports subtraction, so "text" can not be used here.
> IIRC, the sticking point was defining a reasonably datatype-independent
> (i.e. extensible) notion of distance.

Why it is not possible just to locate "-" or "+ operator for this type?
I do not see any difference here with locating comparison operator 
needed for sorting.

-- 
Konstantin Knizhnik
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