Re: retrieve grouping sets/rollup rows

From: James Keener <jim(at)jimkeener(dot)com>
To: Tom Smith <tomsmith1989sk(at)gmail(dot)com>
Cc: PostgreSQL General <pgsql-general(at)postgresql(dot)org>
Subject: Re: retrieve grouping sets/rollup rows
Date: 2016-03-14 02:12:04
Message-ID: 56E61DF4.6040308@jimkeener.com
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Why? You're already provided with this information: NULL fields are not
being used in the grouping set for the row. Moreover, it would seem to
be an implementation- and run-time- dependent value, as there is no
reason group by grouping set (a,b), (c,d) couldn't be executed in
written order, or (c,d) first depending on a lot of things.

Forcing the implementation to conform to a certain way of doing things
is asking for someone to ask why a certain optimization isn't being
performed later on.

My $0.02.

Jim

On 03/13/2016 10:07 PM, Tom Smith wrote:
> It would help if the resultset has some param to mark which is which
> with the grouping sets index.
> for example, the results for (a,b,c,d) would be marked as for index =0,
> (b,c,d) would be index=1
>
> On Sun, Mar 13, 2016 at 9:52 PM, James Keener <jim(at)jimkeener(dot)com
> <mailto:jim(at)jimkeener(dot)com>> wrote:
>
> Do you want to know if a row is from the (a,b) or (c,d) group? All rows
> will contain (a,b,c,d) but (a,b) will be NULL for the (c,d) grouping
> sets, and vice-versa.
>
> Jim
>
> On 03/13/2016 09:45 PM, Tom Smith wrote:
> > Hello:
> >
> > With JDBC, how can I tell which row is for which grouping sets or
> rollup
> > using result sets
> >
> > Thanks
> >
> >
>
>

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