Re: contracting tables
От | Jeff Eckermann |
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Тема | Re: contracting tables |
Дата | |
Msg-id | 20011130153854.46705.qmail@web20801.mail.yahoo.com обсуждение исходный текст |
Ответ на | contracting tables ("Peter T. Brown" <peter@memeticsystems.com>) |
Ответы |
Re: contracting tables
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Список | pgsql-sql |
If you don't have a lot of indexes, sequences, referential integrity constraints etc. the easiest way would be: SELECT INTO table2 DISTINCT * FROM table1; DROP table1; ALTER TABLE table2 RENAME TO table1; Then recreate your other objects/constraints. If you want to do it in place, then: DELETE FROM table1 WHERE EXISTS ( SELECT * FROM table1 AS t1 WHERE t1.key < table1.key ); You will need an index on your "key" value, or this will take a long time on a large table. --- "Peter T. Brown" <peter@memeticsystems.com> wrote: > Hi-- > > I have a table with many records, some of which are > duplicates (there is no > unique constraints). How can I contract this table > to remove any of these > duplicate records? Like when using GROUP BY in a > select statement, except > that I want to just remove the extra entries from > this table directly... Any > ideas? > > > Thanks, > > Peter Brown > > > ---------------------------(end of > broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please > send an appropriate > subscribe-nomail command to majordomo@postgresql.org > so that your > message can get through to the mailing list cleanly __________________________________________________ Do You Yahoo!? Yahoo! GeoCities - quick and easy web site hosting, just $8.95/month. http://geocities.yahoo.com/ps/info1
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