Re: get certain # of recs
От | Andrew Gould |
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Тема | Re: get certain # of recs |
Дата | |
Msg-id | 20010914145825.73798.qmail@web13406.mail.yahoo.com обсуждение исходный текст |
Ответ на | Re: get certain # of recs (Ian Barwick <SUNGLASSESbarwick@gmx.net>) |
Ответы |
CLUSTER (was Re: get certain # of recs)
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Список | pgsql-general |
You might also want to look at the SQL command CLUSTER, which physically reorders the table rows based upon an existing index. Andrew Gould --- Ian Barwick <SUNGLASSESbarwick@gmx.net> wrote: > Mike S. Nowostawsky wrote: > > > How can one select only a certain number of > records in Postgres? > > > > In other SQL langs we can use, say, for the first > 20 recs: > > > > select * from tablename where rownum < 21; > > > > WHAT should 'rownum' be to make this select > work... OR is there a diff > > syntax? > > use the LIMIT clause, e.g. > > SELECT * FROM tablename LIMIT 20 > > for the first 20 rows, or > > SELECT * FROM tablename LIMIT 10,20 > > for 10 rows beginning from the 20th row (or possibly > the other way round, > the caffeine isn't working yet ;-) > > When using LIMIT it is generally advisable to also > use ORDER BY in order to > guarantee consistent result sets over repeated > queries. > > HTH > > Ian Barwick > > > -- > Ian Barwick - Developer > http://www.akademie.de > > Remove SUNGLASSES to reply ;-) > > ---------------------------(end of > broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html __________________________________________________ Terrorist Attacks on U.S. - How can you help? Donate cash, emergency relief information http://dailynews.yahoo.com/fc/US/Emergency_Information/
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