From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ankit Kumar Pandey <itsankitkp@gmail.com>
cc: pgsql-sql@lists.postgresql.org
Subject: Re: [QUESTION] Window function with partition by and order by
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References: <7f9f9b1d-b612-d0bd-4674-cfb5a8b2d343@gmail.com>
Comments: In-reply-to Ankit Kumar Pandey <itsankitkp@gmail.com>
	message dated "Sun, 27 Nov 2022 21:38:33 +0530"
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Date: Sun, 27 Nov 2022 11:28:04 -0500
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Ankit Kumar Pandey <itsankitkp@gmail.com> writes:
> Question is: Average of id for partition name (A) should be 6/4 = 1.5 
> for all rows in that partition but this result is seen only at the last 
> one row in partition (A). Am I missing here something?

https://www.postgresql.org/docs/current/tutorial-window.html

particularly:

    By default, if ORDER BY is supplied then the frame consists of all
    rows from the start of the partition up through the current row, plus
    any following rows that are equal to the current row according to the
    ORDER BY clause.

			regards, tom lane