From: | Jeff Eckermann <jeff_eckermann(at)yahoo(dot)com> |
---|---|
To: | "Peter T(dot) Brown" <peter(at)memeticsystems(dot)com>, pgsql-sql(at)postgresql(dot)org |
Subject: | Re: contracting tables |
Date: | 2001-11-30 15:38:54 |
Message-ID: | 20011130153854.46705.qmail@web20801.mail.yahoo.com |
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Thread: | |
Lists: | 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(at)memeticsystems(dot)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
>
>
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