| 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: | 19251.959223598@sss.pgh.pa.us |
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| 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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