Re: performance comparison: DISTINCT and GROUP BY

Hi Devrim,

You can use the EXPLAIN ANALYZE syntax to find out quite easily.

Chris

----- Original Message -----
From: "Devrim GUNDUZ" <devrim(at)oper(dot)metu(dot)edu(dot)tr>
To: "PostgreSQL Mailing Lists-SQL" <pgsql-sql(at)postgresql(dot)org>
Sent: Monday, August 19, 2002 7:22 PM
Subject: [SQL] performance comparison: DISTINCT and GROUP BY

>
> Hi,
>
> We have two different queries:
>
> SELECT name,surname FROM my_table GROUP BY name;
>
> and
>
> SELECT DISTINCT on(name) name,surname * FROM my_table;
>
> which gives us the same result.
>
> Do these queries differ by their performances? I mean, which one works
> faster? DISTINCT or GROUP BY?
>
> Best regards.
>
> --
>
> Devrim GUNDUZ
>
> devrim(at)oper(dot)metu(dot)edu(dot)tr Tel : (312) 295 9318
> devrim(dot)gunduz(at)linux(dot)org(dot)tr Faks : (312) 295 9494
>
> Web : http://devrim.oper.metu.edu.tr
> -------------------------------------
>
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