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Re: possible bug with group by?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Joseph Shraibman <jks(at)selectacast(dot)net>
Cc: Stephan Szabo <sszabo(at)kick(dot)com>, pgsql-sql(at)postgresql(dot)org
Subject: Re: possible bug with group by?
Date: 2000-05-25 02:59:58
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-sql
Joseph Shraibman <jks(at)selectacast(dot)net> writes:
> But why would group by need to sort it?  To insert it into a tree to
> make lookups of distinct values faster?

No, to bring identical values together.  GROUP BY and DISTINCT are both
implemented as basically a "sort | uniq" pipeline.

			regards, tom lane

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