From: | Shaun Thomas <sthomas(at)peak6(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov> |
Cc: | Nikolas Everett <nik9000(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Best way to get the latest revision from a table |
Date: | 2011-01-15 19:54:29 |
Message-ID: | D247E79EFD801E40A9449A9724F6295B4C5F5F4E@spswchi6mail1.peak6.net |
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Thread: | |
Lists: | pgsql-performance |
> Shaun's example is a bit off: normally, when using DISTINCT ON, you want
> an ORDER BY key that uses all the given DISTINCT keys and then some
> more. To get the max revision for each a/b combination it ought to be
Hah, well i figured I was doing something wrong. I just thought about it a little bit, said to myself: "Hey, I've used this before to get the most recent x for a bunch of y without a sub-query. We always used it to get the newest update to an event log.
But that's why I said I was probably misunderstanding something. :) I was trying to pick apart the logic to his temp tables and saw the max(b) and it threw me off. Glad you're around to set it straight. Heh.
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