Re: GROUP BY overlapping (tsrange) entries

From: Michael Moore <michaeljmoore(at)gmail(dot)com>
To: Andreas Joseph Krogh <andreas(at)visena(dot)com>
Cc: postgres list <pgsql-sql(at)postgresql(dot)org>
Subject: Re: GROUP BY overlapping (tsrange) entries
Date: 2016-01-29 18:17:51
Message-ID: CACpWLjNVQio0bMUbBC1-_qNYQRi9vzMibxwQV1oBcT5JeOgyYQ@mail.gmail.com
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I was thinking along the lines that David J's link shows. But now I see
that it's already been done and documented. So, I got nothing.

On Fri, Jan 29, 2016 at 9:30 AM, Andreas Joseph Krogh <andreas(at)visena(dot)com>
wrote:

> På fredag 29. januar 2016 kl. 17:59:52, skrev David G. Johnston <
> david(dot)g(dot)johnston(at)gmail(dot)com>:
>
> On Fri, Jan 29, 2016 at 9:45 AM, Andreas Joseph Krogh <andreas(at)visena(dot)com>
> wrote:
>
>> På fredag 29. januar 2016 kl. 02:43:37, skrev Andreas Joseph Krogh <
>> andreas(at)visena(dot)com>:
>>
>> På fredag 29. januar 2016 kl. 02:11:52, skrev Andreas Joseph Krogh <
>> andreas(at)visena(dot)com>:
>>
>> På fredag 29. januar 2016 kl. 02:02:46, skrev Michael Moore <
>> michaeljmoore(at)gmail(dot)com>:
>>
>> It is unclear to me how you got from your input data to your expected
>> output. If you are "trying to count() overlapping entries" then it would
>> seem to me that you would only have only one value for the count. Either a
>> range overlaps or it does not.
>>
>>
>> Oh, sorry, the count was in wrong order.
>>
>> Let me explain,
>>
>> insert into event(name, start_time, end_time)
>> values('a', '2015-12-20', NULL)
>> , ('a', '2015-12-20', '2015-12-31')
>> , ('a', '2015-12-25', '2016-01-01')
>> , ('b', '2015-11-20', '2015-11-24')
>> , ('c', '2016-02-01', '2016-02-03')
>> , ('c', '2016-02-01', '2016-02-04') , ('c', '2016-02-01', NULL)
>> ;
>>
>> All 'a', 'b' and 'c' have points in common, with count a=3, b=1, c=3.
>>
>>
>> Note that the 'name'-column here is just to explain what I'm after and
>> that I have no such column.
>>
>>
>> Any clever hints anyone?
>>
>>
>
> ​Maybe this will help...?
>
> ​
> https://wiki.postgresql.org/wiki/Range_aggregation
>
> ​David J.​
>
>
> Yea, I've seen it, but don't like it.
>
> I was (am) hoping some clever PG-guy would step up and craft som clever
> GROUP BY stuff like "GROUP BY magic_gist_equals(tsrange with &&)"
>
> --
> *Andreas Joseph Krogh*
> CTO / Partner - Visena AS
> Mobile: +47 909 56 963
> andreas(at)visena(dot)com
> www.visena.com
> <https://www.visena.com>
>
>

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