Re: making queries more effecient - Mailing list pgsql-sql

From Chad Thompson
Subject Re: making queries more effecient
Date
Msg-id 033301c281f2$aed1f7e0$32021aac@chad
Whole thread Raw
In response to making queries more effecient  ("Peter T. Brown" <peter@memeticsystems.com>)
List pgsql-sql
This should be all you need.

insert into VisitorPointer839 ("VisitorID")
select VisitorID
from ProgramEvent
Where ProgramID = 10
and Type = 0
group by VisitorID

You dont need order by because its not important the order it goes in the
database, just the order that it comes out.
I have found that group by works faster than distinct in some cases.  You
may have to test it for your senario.

Thanks
Chad

----- Original Message -----
From: "Peter T. Brown" <peter@memeticsystems.com>
To: <pgsql-sql@postgresql.org>
Sent: Friday, November 01, 2002 3:24 PM
Subject: [SQL] making queries more effecient


> Hi. I have this query that I have been trying to reduce to a single
> statement, but haven't figured out how. Am I missing something?
>
> CREATE TEMP TABLE temp20561149207391 AS SELECT DISTINCT ON ("VisitorID")
> "VisitorID","Type" FROM "ProgramEvent" WHERE "ProgramID" = 10 ORDER BY
> "VisitorID","Created" DESC;INSERT INTO "VisitorPointer839" ("VisitorID")
> SELECT temp20561149207391."VisitorID" FROM temp20561149207391  WHERE
> temp20561149207391."Type" = 0
>
>
> Thanks
>
>
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