Re: [HACKERS] is it possible to use LIMIT and INTERSECT ?
От | Oleg Bartunov |
---|---|
Тема | Re: [HACKERS] is it possible to use LIMIT and INTERSECT ? |
Дата | |
Msg-id | Pine.GSO.3.96.SK.991018122740.11898E-100000@ra обсуждение исходный текст |
Ответ на | Re: [HACKERS] is it possible to use LIMIT and INTERSECT ? (Hannu Krosing <hannu@tm.ee>) |
Список | pgsql-hackers |
On Mon, 18 Oct 1999, Hannu Krosing wrote: > Date: Mon, 18 Oct 1999 08:22:31 +0000 > From: Hannu Krosing <hannu@tm.ee> > To: Oleg Bartunov <oleg@sai.msu.su> > Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgreSQL.org > Subject: Re: [HACKERS] is it possible to use LIMIT and INTERSECT ? > > Oleg Bartunov wrote: > > > > Tom, > > > > patch was applied smoothly to 6.5.2 > > What's the syntax ? > > > > select a.msg_id, c.status_set_date, c.title > > from Message_Keyword_map a, messages c, keywords d > > where c.status_id =1 and d.name ~* 'moon' and a.key_id=d.key_id > > and c.msg_id=a.msg_id > > intersect > > select a.msg_id, a.status_set_date, a.title from messages a > > where a.status_id = 1 and a.title ~* 'moon' limit 5; > > > > produces (10 rows) > > > > select a.msg_id, c.status_set_date, c.title > > from Message_Keyword_map a, messages c, keywords d > > where c.status_id =1 and d.name ~* 'moon' and a.key_id=d.key_id > > and c.msg_id=a.msg_id limit 5 > > intersect > > select a.msg_id, a.status_set_date, a.title from messages a > > where a.status_id = 1 and a.title ~* 'moon' limit 5; > > > > As the limit is applied to the final result, I guess you can have only one > LIMIT per query. > > So try removing the limit 5 before intersect . > This was my first try (look above). It works but produces 10 rows instead of 5. Oleg > ----------- > Hannu > _____________________________________________________________ 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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