Subject: Re: query based on row number for psql8.3
To: emilu@encs.concordia.ca, pgsql-sql@postgresql.org
References: <56F2D9C4.9010304@encs.concordia.ca>
From: Adrian Klaver <adrian.klaver@aklaver.com>
Message-ID: <56F2DB73.2070703@aklaver.com>
Date: Wed, 23 Mar 2016 11:07:47 -0700
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On 03/23/2016 11:00 AM, Emi wrote:
> Hello,
>
> For psql8.3, is there a simple way to query based on row number please?

First FYI, 8.3 is 3 years past its end of life.

Second, Postgres does not have a built in row_num. Anything that could 
be cobbled together would be dependent on the ordering specified.

So what exactly are you trying to do?
In other words what is row_num supposed to represent?

>
> For example,
>
> select  case
>                      when row_num=1 THEN    t1.tot_hr
>                      ELSE                                  t1.tot_hr -
> t1.pre_hr
>            END
> FROM  t1 ;
>
>
>
>
>


-- 
Adrian Klaver
adrian.klaver@aklaver.com


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