From: Tony Yang <gnalesad@hotmail.com>
To: pgsql-sql@postgresql.org
Subject: help with scheme changes to live system.
Date: Thu, 19 Aug 2004 22:00:56 +0000
Message-ID: <BAY1-F34ktJ3GOeym8Y000966ee@hotmail.com> (raw)
Hi Gurus,
Please forgive this naive question:
Say, I have a table (containerId, itemId) where for each containerId there
are several rows (different itemId value) in that table. Now I want to give
those rows (with same containerId) a sequence, so add one colum there to
make it become (containerId, itemId, sequence); how do I make such changes
through SQL?
I know how to alter the table to insert that new column, but how do I
populate the existed rows on that new column? note the sequence dose not
need to confirm to any sorting of other columns, i.e., as long as there is a
sequence is ok. for example, if I already have :
containerId | itemId |
1 1001
1 1002
1 1003
2 2001
2 2002
then either
containerId | itemId | sequence
1 1001 0
1 1002 1
1 1003 2
2 2001 1
2 2002 0
or
containerId | itemId | sequence
1 1001 2
1 1002 1
1 1003 0
2 2001 0
2 2002 1
are all OK.
Thanks,
Gnale
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Cc: gnalesad@hotmail.com
Subject: Re: help with scheme changes to live system.
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