Re: How is sorting work?

Thanks Steve!

Just want to get confirmation that postgres does not use any special rules

When no sorting order specified.

Thanks,
Quang.

On 5/30/14 5:20 PM, "Steve Atkins" <steve(at)blighty(dot)com> wrote:

>
>On May 30, 2014, at 5:13 PM, Quang Thoi <Quang_Thoi(at)symantec(dot)com> wrote:
>
>> Any one knows how sorting works?
>>
>> I am using postgresql 9.3 and runs on Linux machines.
>> I see different sorting order for the same set of return data.
>>
>> On linux machines, databases are configured the same.
>> Database have encoding set to 'utf8' and locale='C'
>>
>> query:
>> Select host_id, host_name from host_view order by host_id
>>
>> hos_id (character varying 128)
>> host_name (character varying 255)
>>
>> - On one linux machine (locate in U.S) , the query returned following:
>>
>> host_id host_name
>> ------------ ------------------
>> "00017486"; "lnx2.xx.yy.com"
>> "00017486"; "lnx1.xx.yy.com"
>>
>> - On a different linux machine (locate in India), the query returned
>>following:
>>
>> host_id host_name
>> ------------ ------------------
>> "00017486"; "lnx1.xx.yy.com"
>> "00017486"; "lnx2.xx.yy.com"
>
>Both results are correct. If you don't specify a sort order, postgresql
>will return results in whatever order is convenient - which won't be
>consistent from query to query or machine to machine.
>
>You're only sorting by host_id. If you want to sort consistently by
>host_id and host_name, so that the sort order is well defined for
>identical host_ids, you'll want to do something like
>
>select host_id, host_name from host_view order by host_id, host_name.
>
>Cheers,
> Steve
>
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