From: george young <gry@ll.mit.edu>
To: pgsql-sql@postgresql.org
Subject: how to update table to make dup values distinct
Date: Thu, 10 Nov 2005 10:58:18 -0500
Message-ID: <20051110105818.4dc51e8c.gry@ll.mit.edu> (raw)
[PostgreSQL 7.4RC2 on i686-pc-linux-gnu](I know, I know... must upgrade soon)
I have a table mytable like:
i | txt
---+-------
1 | the
2 | the
3 | rain
4 | in
5 | mainly
6 | spain
7 | stays
8 | mainly
9 | in
I want to update it, adding a ':' to txt so that each txt value is unique.
I don't care which entry gets changed. I tried:
update mytable set txt=mytable.txt || ':' from mytable t2 where mytable.txt=t2.txt and mytable.i=t2.i;
but this updated both duplicated entries.
Um, there may sometimes be 3 or 4 duplicates, not just two. For these, I can add multiple colons, or one each of an assortment of characters, say ':+*&^#'.
Performance does not matter here. The real table has 30K rows, ~200 dups.
To clarify, I want to end up with something like:
1 | the
2 | the:
3 | rain
4 | in
5 | mainly:
6 | spain
7 | stays
8 | mainly
9 | in:
-- George
--
"Are the gods not just?" "Oh no, child.
What would become of us if they were?" (CSL)
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To: pgsql-sql@postgresql.org
Cc: gry@ll.mit.edu
Subject: Re: how to update table to make dup values distinct
In-Reply-To: <20051110105818.4dc51e8c.gry@ll.mit.edu>
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