Re: I need some magical advice

Hi,

yes, there is a serial as primary key. Lets call it "id".
Therfore one could use this to find the oldest record.


Regards  Andreas



Oliveiros Cristina schrieb:
> 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
>>
>>
>>
>> -- 
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>
>