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 02:37:13
Message-ID: 56E623D9.9090306@jimkeener.com
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It just dawned on me that you may note have meant having them in a
specific sequence in the result set. Even still, I think it's much more
clear being explicit with what rows are included and which aren't.

Jim

On 03/13/2016 10:12 PM, James Keener wrote:
> 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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