From: Tom Lane <tgl@sss.pgh.pa.us>
To: Oliver Ford <ojford@gmail.com>
cc: Erik Rijkers <er@xs4all.nl>, Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: Add RANGE with values and exclusions clauses to the Window
 Functions
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Comments: In-reply-to Oliver Ford <ojford@gmail.com>
	message dated "Wed, 10 Jan 2018 06:56:41 +0000"
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Date: Wed, 10 Jan 2018 02:06:18 -0500
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Oliver Ford <ojford@gmail.com> writes:
> On Tuesday, 9 January 2018, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> So the approach I'm imagining now is a datatype-specific support function
>> along the lines of
>> 	in_range(a, b, delta) returns bool
>> Likely there are two of these, one each for the PRECEDING and FOLLOWING
>> cases.

> Would you prefer two functions, or a single function with a parameter for
> PRECEDING/FOLLOWING? Maybe:
>   in_range(a, b, delta, following) returns bool

You could do it that way too.  The two-function approach seems a little
cleaner and easier to document IMO, but it would create more catalog
bloat, so there's that.  I don't have a strong preference.

			regards, tom lane