Re: Selecting latest value II
От | Chris Ruprecht |
---|---|
Тема | Re: Selecting latest value II |
Дата | |
Msg-id | 009501c141e8$8cb56200$5dd26383@corp.compucom.com обсуждение исходный текст |
Ответ на | Re: Selecting latest value II (Haller Christoph <ch@rodos.fzk.de>) |
Список | pgsql-sql |
what about using 'distinct' in you select statement? ----- Original Message ----- From: "Haller Christoph" <ch@rodos.fzk.de> To: "Patrik Kudo" <kudo@partitur.se> Cc: <pgsql-sql@postgresql.org> Sent: Thursday, September 20, 2001 11:02 AM Subject: Re: [SQL] Selecting latest value II > What do you mean by > "the latest val for each userid" > I cannot understand how a value of type integer > can have a attribute like "latest". > Sorry, but I need at least a bit more information. > Regards, Christoph > > > > On Thu, 20 Sep 2001, Haller Christoph wrote: > > > > > Try > > > create NEWtable (userid text, val integer, ts timestamp); > > > insert into NEWtable > > > select userid, val, max(ts) from table group by userid, val; > > > > That won't work. That will give me multiple userid-val combinations. Sure, > > the userid-val combinations will be unique, but I want unique userids > > with only the latest val for each userid. > > > > /Patrik Kudo > > > > > > > > > > Hi, > > > > > > > > I have a table which basically looks like this: > > > > > > > > create table (userid text, val integer, ts timestamp); > > > > > > > > This table holds multiple values for users, timestamped for history > > > > reasons. > > > > > > > > Now I need to fetch the latest val for each userid to insert into a new > > > > table (with about the same schema, except for uniqueness on userid). > > > > I belive this should be a trivial task, but I'm experience total lack of > > > > insight here... > > > > > > > > Comments? > > > > > > > > /Patrik Kudo > > > > > > > > > > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com
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