Re: making queries more effecient
От | Chad Thompson |
---|---|
Тема | Re: making queries more effecient |
Дата | |
Msg-id | 033301c281f2$aed1f7e0$32021aac@chad обсуждение исходный текст |
Ответ на | making queries more effecient ("Peter T. Brown" <peter@memeticsystems.com>) |
Список | 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 > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to majordomo@postgresql.org so that your > message can get through to the mailing list cleanly >
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