Andreas,
Does your table has any field that can be used as primary key? Any "ID"
field?
Best,
Oliveiros
----- Original Message -----
From: "Andreas" <maps...@gmx.net>
To: <pgsql-sql@postgresql.org>
Sent: Thursday, January 29, 2009 11:56 AM
Subject: [SQL] I need some magical advice
Hi,
I'd like to update some records in a table.
Those have a status_id and among other columns a varchar with a name and a
create_date.
The status_id is 0 if nothing was done with this record, yet.
For some reasons I've got double entries which I now want to flag to -1 so
that they can be sorted out without actually deleting them since there are
other tables referencing them.
From every group that shares the same name all should get status_id set
to -1 where status_id = 0.
The tricky bit is:
How could I provide, that 1 of every group survives, even then when all
have status_id = 0?
Sometimes 2 of a group are touched so both have to stay.
e.g.
c_date, status_id, name
2008/01/01, 0, A --> -1
2008/01/02, 1, A --> do nothing
2008/01/03, 0, A --> -1
2008/01/01, 0, B --> do nothing (single entry)
2008/01/01, 0, C --> do nothing (oldest 0 survives)
2008/01/02, 0, C --> -1
2008/01/01, 1, D --> do nothing
2008/01/02, 1, D --> do nothing
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