Re: sql
От | Mike Rylander |
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Тема | Re: sql |
Дата | |
Msg-id | b918cf3d041025042021ca123e@mail.gmail.com обсуждение исходный текст |
Ответ на | sql ("cristivoinicaru" <cristivoinicaru@dmhi.ct.ro>) |
Ответы |
Re: sql
|
Список | pgsql-sql |
On Mon, 25 Oct 2004 10:13:37 +0200, cristivoinicaru <cristivoinicaru@dmhi.ct.ro> wrote: > I have a postgres table like this: > > CREATE TABLE "temp50" ( > "gc" character varying(36), > "co" character varying(7), > "data" date, > "ora" smallint > > ); > > It contains the following records: > > 5003707G9G9419 22012BB 10-14-2004 82 > 5003707G9G9419 22012BC 10-14-2004 44 > 5003707G9G9419 22022BB 10-14-2004 82 > 5003707G9G9420 22022BC 10-18-2004 49 > > I'd like the result of the sql interogation to be like this: > > 5003707G9G9419 22012BB 10-14-2004 82 > 5003707G9G9420 22022BC 10-18-2004 49 > > Explanations: > I want like sql interogation to select only one record from each "gc" group > record (who has the same code "gc" (that means that the "gc" field will be > unique key)) with the following two condition: > 1)from each "gc" group of records to select the record who has the value of > "ora" field maxim. > 2)if two ore more record have the same value of the maxim value of the "ora" > to select oly one of them Try: SELECT * FROM temp50 GROUP BY gc ORDER BY ora DESC; --miker > > Thanks! > > ---------------------------(end of broadcast)--------------------------- > TIP 8: explain analyze is your friend >
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