Re: I need some magical advice

Andreas,
Does your table has any field that can be used as primary key? Any "ID" 
field?

Best,
Oliveiros


----- Original Message ----- 
From: "Andreas" <maps.on@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
>
>
>
> -- 
> Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-sql
>