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could not create unique index, table contains duplicated values

From: "Christian Hofmann" <christian(dot)hofmann(at)gmx(dot)de>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: could not create unique index, table contains duplicated values
Date: 2005-11-27 21:45:27
Message-ID: 000a01c5f39b$e1bf2c90$7b00a8c0@taschenrechner (view raw, whole thread or download thread mbox)
Lists: pgsql-novice

I have a table with two columns (id, names).

At this time there is no index, because i have not needed any one.

There are about 120 million rows. Now I want to delete all duplicate rows.
I thought I could just create a unique index and postgresql qould do the
rest. But ok. Maybe postgresql didn't know which rows to delete.

Is there a query that will delete all rows where the same name is more than
one time in the table?
I only want to have every name once in the table.

My method to write a programm, select every row and cvompare it to the
others would be very slow.

There is something with a having statement, but I don't get the clue to
build that statement.

Can you help me?

Thank you very much,



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Next:From: Oliver ElphickDate: 2005-11-27 22:24:38
Subject: Re: could not create unique index, table contains
Previous:From: Andreas KretschmerDate: 2005-11-27 07:03:19
Subject: Re: MSSQL migration questions

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