Re: How is sorting work? - Mailing list pgsql-general

From Rajeev rastogi
Subject Re: How is sorting work?
Date
Msg-id BF2827DCCE55594C8D7A8F7FFD3AB7713DDFCB19@SZXEML508-MBX.china.huawei.com
Whole thread Raw
In response to How is sorting work?  (Quang Thoi <Quang_Thoi@symantec.com>)
List pgsql-general

 

As your query contains order by on host_id, so it will be sorted only based on host_id. Since in your case host_id is same for both rows, the order in which host_name will be selected will be absolutely random.

If you want query to returns rows sorted on host_name also, then you should add host_name in order by clause as below:

 

Select host_id, host_name from host_view order by host_id, host_name;

So in this case first it will be sort based on host_id and then on host_name.

 

From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Quang Thoi
Sent: 31 May 2014 05:44
To: pgsql-general@postgresql.org
Subject: [GENERAL] How is sorting work?

 

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"

 

Thanks,

Quang.

 

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