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From: "Phil Endecott" <spam_from_postgresql_sql@chezphil.org>
To: Graham Leggett <minfrin@sharp.fm>, pgsql-sql@postgresql.org
Subject: Re: Normalising an existing table - how?
Date: Thu, 24 Jun 2004 16:55:47 -0400
Message-Id: <7184150@chezphil.org>
In-Reply-To: <40DB229C.9040306@sharp.fm>
References: <40DB229C.9040306@sharp.fm>

Graham Leggett wrote:
> I have an existing table containing a column in it containing
> a money value. I would like to normalise this column into a
> separate table, as the money value is to be expanded to contain
> a tax value, etc.
> 
> I have been trying to find a SQL query that will do the
> following:
> 
> - Select the money column from the table
> - Populate the new normalised table with each row containing
>   the value from the original money column
> - Write the primary keys of the new rows in the normalised
>   table, back to a new column in the original table added for
>   this purpose.

Change the order.  Do the third step first:

alter table T add column X integer;
update T set X = nextval(somesequence);

Now do the first and second steps together:

select X, MoneyColumn from T into NewTable;

Is this the sort of thing you need?

--Phil.