Re: [SQL] count() question
От | Oleg Bartunov |
---|---|
Тема | Re: [SQL] count() question |
Дата | |
Msg-id | Pine.GSO.3.96.SK.991219211402.11677F-100000@ra обсуждение исходный текст |
Ответ на | Re: [SQL] count() question ("Mitch Vincent" <mitch@venux.net>) |
Список | pgsql-sql |
I recall Jan wrote about why it's impossible to get count() with LIMIT clause. Check hackers mail-archive. But I do need also such a feature. regards, Oleg On Sun, 19 Dec 1999, Mitch Vincent wrote: > Date: Sun, 19 Dec 1999 12:33:40 -0500 > From: Mitch Vincent <mitch@venux.net> > To: Peter Eisentraut <peter_e@gmx.net> > Cc: pgsql-sql@postgreSQL.org > Subject: Re: [SQL] count() question > > > Why do you want to avoid that? If you need two different results then you > > probably have to use two different queries. > > Speed, resource consumption and there might not be any need for it :-) > > >I assume you need the count to > > display something like "x matches found" and use LIMIT/OFFSET to step > > through them page by page. > > I do use LIMIT / OFFSET and that's part of the problem. I can't get a total > count from a query when I use LIMIT and OFFSET (at least I don't know how).. > > > In that case there is really no way but to > > query twice. If your query is really complicated and slow you might want > > to put the complete query results in a temporary table, and select the > > count and the to-be-displayed data from there. > > Indeed, that might be a better way to structure the search however at this > point I have to work withion what is already there (there is a huge > application built around the search engine). I am going to totally re-write > this but can't do that now, now I needed to add some functionality with a > minimum impact on the rest of the application. > > If I have to do another query, so be it. I just wanted to make sure there > wasn't a way for me to do something like : > > select * from applicants as a, count(*) as total where a.status = 'A' limit > 10 offset 0 > > Of course I know I can't do that like that but thought there might be a > substitute or alternative way of getting the count from within the query. > > -Mitch > > > > > > > ************ > _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83
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