Re: Re: BUG #10256: COUNT(*) behaves sort of like RANK() when used over a window containing an ORDER BY
От | Tom Lane |
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Тема | Re: Re: BUG #10256: COUNT(*) behaves sort of like RANK() when used over a window containing an ORDER BY |
Дата | |
Msg-id | 16221.1399514921@sss.pgh.pa.us обсуждение исходный текст |
Ответ на | Re: Re: BUG #10256: COUNT(*) behaves sort of like RANK() when used over a window containing an ORDER BY (David Johnston <david.g.johnston@gmail.com>) |
Список | pgsql-bugs |
David Johnston <david.g.johnston@gmail.com> writes: > On Wed, May 7, 2014 at 8:07 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> [ looks at SQL standard... ] The standard uses "peer" in this way too, >> so that's where we got the term from. Because of that, I'm unwilling >> to adopt your suggestion of thinking that "peer" means "member of the >> same partition". > I guess rows falling into the same partition could be deemed "member" rows; > as in having membership in the partition. Works for me. > Does the standard provide a word for tuples that get placed into the same > partition? Not that I noticed, but I didn't search hard. The index of SQL:2011 has one entry for "peer", pointing to this definition under 10.10 <sort specification list>: i) Two rows that are not distinct with respect to the <sort specification>s are said to be peers of each other. The relative ordering of peers is implementation-dependent. so in their usage it's not even specific to windows. The terminology for windows seems to be mostly defined in 4.15.14, and I don't see a term in there for the rows belonging to a partition. regards, tom lane
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