Re: grouping subsets

the table may include up to maybe 30 entries per day, average maybe 10-15
After a year this makes about 10.000 entries - maximum, average about 5000 entries.

For the problem described I have to use a Microsoft SQL database and would like to use pure SQL.
As I use postgres on my Linux servers I found this newsgroup and thought I ask here.

Thanks!
Rainer

Am 29.07.2010 15:31, schrieb Oliveiros d'Azevedo Cristina:
> Fine.
>
> Please advice me,
>
> How long can
> your table be? Thousands? Millions of records?
>
> Do you really need it in pure SQL
> ?
>
> It seems to me that it might be possible, I'm just affraid that the query would become too complex and thus slow...
>
> Best,
> Oliveiros
>
> ----- Original Message ----- From: "Rainer Stengele" <rainer(dot)stengele(at)diplan(dot)de>
> To: "Oliveiros d'Azevedo Cristina" <oliveiros(dot)cristina(at)marktest(dot)pt>
> Cc: <pgsql-sql(at)postgresql(dot)org>
> Sent: Thursday, July 29, 2010 1:10 PM
> Subject: Re: grouping subsets
>
>
>> No. This is by accident.
>> We have to assume that the combinations do change anytime, and many times per day.
>>
>> So
>>
>> "Or is it possible to have the same combination on one day with several sets?"
>>
>> YES!
>>
>> Rainer
>>
>>
>>
>> Am 29.07.2010 13:47, schrieb Oliveiros d'Azevedo Cristina:
>>> Yes. This is somewhat more complicated because it has more constraints.
>>> I've noticed that a given combination doesn't appear with holes on a certain day.
>>>
>>> For ex, on a daily basis, we have every three key combinations together.
>>>
>>> We dont have things like
>>> 2010-7-01 1726 3212 1428
>>> 2010-7-01 1726 3212 1428
>>> ... 318 1846 1012
>>> 2010-7-01 1726 3212 1428
>>>
>>> Can I assume that, for a certain day , the records for the same three combination are all together? There is just one set per day for a given combination?
>>>
>>> Or is it possible to have the same combination on one day with several sets?
>>>
>>> Best,
>>> Oliveiros
>>>
>>>
>>> ----- Original Message ----- From: "Rainer Stengele" <rainer(dot)stengele(at)diplan(dot)de>
>>> Newsgroups: gmane.comp.db.postgresql.sql
>>> To: "Oliveiros d'Azevedo Cristina" <oliveiros(dot)cristina(at)marktest(dot)pt>
>>> Cc: <>
>>> Sent: Thursday, July 29, 2010 10:41 AM
>>> Subject: Re: grouping subsets
>>>
>>>
>>>> Howdy Cristina,
>>>>
>>>> unfortunately things are more complicated. I have inserted an excerpt of the real data here:
>>>>
>>>> ================================================================================
>>>> TableID MasterID dtBegin dtEnd idR idL idB consumption
>>>> 4057312 295530 2010-07-01 00:59:21.077 2010-07-01 01:32:59.670 1726 3212 1428 279
>>>> 4061043 295574 2010-07-01 01:59:31.137 2010-07-01 02:32:09.373 1726 3212 1428 183
>>>> 4083397 295838 2010-07-01 07:57:51.327 2010-07-01 08:28:28.117 318 1846 1012 30
>>>> 4090858 295920 2010-07-01 09:52:33.777 2010-07-01 10:31:34.393 318 1846 1012 487
>>>> 4094589 295961 2010-07-01 10:47:59.370 2010-07-01 11:32:20.903 318 1846 1012 472
>>>> 4098330 296013 2010-07-01 11:58:53.890 2010-07-01 12:31:35.730 318 1846 1012 195
>>>> 4102069 296058 2010-07-01 12:36:19.170 2010-07-01 13:32:13.950 318 1846 1012 338
>>>> 4105809 296102 2010-07-01 13:58:53.170 2010-07-01 14:02:57.710 318 1846 1012 105
>>>> 4109555 296150 2010-07-01 14:59:11.663 2010-07-01 15:32:33.810 318 1846 1012 187
>>>> 4113305 296194 2010-07-01 15:59:01.797 2010-07-01 16:02:27.260 318 1846 1012 108
>>>> 4117048 296238 2010-07-01 16:20:47.997 2010-07-01 17:32:49.367 318 1846 1012 179
>>>> 4120791 296282 2010-07-01 17:58:27.657 2010-07-01 18:29:01.733 318 1846 1012 256
>>>> 4128291 296370 2010-07-01 19:54:17.687 2010-07-01 20:32:53.850 318 1846 1012 239
>>>> 4132044 296413 2010-07-01 20:31:37.653 2010-07-01 21:29:13.497 318 1846 1012 39
>>>> 4135797 296458 2010-07-01 21:59:13.983 2010-07-01 22:32:46.503 318 1846 1012 157
>>>> 4139572 296506 2010-07-01 22:58:49.530 2010-07-01 23:32:22.543 318 1846 1012 218
>>>> 4142941 296554 2010-07-01 23:59:13.857 2010-07-02 00:32:30.390 318 1846 1012 248
>>>> 4146289 296598 2010-07-02 00:58:55.763 2010-07-02 01:32:41.983 318 1846 1012 204
>>>> 4149616 296642 2010-07-02 01:46:57.357 2010-07-02 02:32:56.983 318 1846 1012 42
>>>> 4152952 296686 2010-07-02 02:55:19.653 2010-07-02 03:32:28.013 318 1846 1012 135
>>>> 4156289 296730 2010-07-02 03:43:52.777 2010-07-02 04:32:55.250 318 1846 1012 743
>>>> 4159624 296774 2010-07-02 04:43:15.310 2010-07-02 05:32:44.547 318 1846 1012 277
>>>> 4162961 296817 2010-07-02 05:58:59.483 2010-07-02 06:32:37.340 318 1846 1012 121
>>>> 4166303 296862 2010-07-02 06:58:50.733 2010-07-02 07:32:39.113 318 1846 1012 239
>>>> 4172981 296950 2010-07-02 07:28:55.293 2010-07-02 09:33:01.200 318 1846 1012 512
>>>> 4176322 296993 2010-07-02 09:59:04.607 2010-07-02 10:33:01.903 318 1846 1012 139
>>>> 4179667 297038 2010-07-02 10:55:27.760 2010-07-02 11:32:56.560 318 1846 1012 722
>>>> 4183012 297082 2010-07-02 11:59:33.650 2010-07-02 12:32:14.700 318 1846 1012 163
>>>> 4186351 297126 2010-07-02 12:23:45.997 2010-07-02 13:32:59.500 318 1846 1012 284
>>>> 4189689 297169 2010-07-02 13:44:21.253 2010-07-02 14:18:05.080 318 1846 1012 254
>>>> 4196371 297258 2010-07-02 16:16:19.123 2010-07-02 16:32:53.437 1706 3541 1511 161
>>>> 4199720 297301 2010-07-02 16:59:35.127 2010-07-02 17:32:57.950 1706 3541 1511 250
>>>> 4203068 297346 2010-07-02 17:59:34.027 2010-07-02 18:32:54.337 1706 3541 1511 302
>>>> 4206413 297389 2010-07-02 18:59:28.730 2010-07-02 19:32:37.950 1706 3541 1511 276
>>>> 4209758 297434 2010-07-02 19:54:00.243 2010-07-02 20:32:57.433 1706 3541 1511 209
>>>> 4213102 297473 2010-07-02 20:49:10.963 2010-07-02 21:30:44.540 1706 3541 1511 76
>>>> 4216447 297511 2010-07-02 21:59:34.810 2010-07-02 22:33:00.603 1706 3541 1511 287
>>>> 4219818 297569 2010-07-02 22:56:52.750 2010-07-02 23:59:31.607 1706 3541 1511 1877
>>>> 4219819 297570 2010-07-02 23:59:21.577 2010-07-03 00:54:40.153 1706 3541 1511 1798
>>>> 4219821 297572 2010-07-03 00:48:03.310 2010-07-03 01:59:37.920 1706 3541 1511 1125
>>>> 4219823 297574 2010-07-03 01:51:01.057 2010-07-03 02:59:45.433 1706 3541 1511 1629
>>>> 4219820 297571 2010-07-03 02:59:29.393 2010-07-03 03:59:54.920 1706 3541 1511 2462
>>>> 4219822 297573 2010-07-03 03:59:18.663 2010-07-03 04:01:48.810 1706 3541 1511 70
>>>> 4225738 297656 2010-07-03 06:13:34.980 2010-07-03 06:28:09.697 1726 3212 1428 46
>>>> 4228694 297695 2010-07-03 06:59:15.560 2010-07-03 07:32:45.653 1726 3212 1428 251
>>>> 4231649 297733 2010-07-03 07:59:11.937 2010-07-03 08:32:57.217 1726 3212 1428 284
>>>> 4234604 297771 2010-07-03 08:57:00.357 2010-07-03 09:32:47.903 1726 3212 1428 227
>>>> 4237559 297809 2010-07-03 09:59:19.813 2010-07-03 10:33:02.063 1726 3212 1428 285
>>>> 4261156 298596 2010-07-04 22:59:09.863 2010-07-04 23:33:45.530 1726 3212 1428 1286
>>>> 4264114 298646 2010-07-04 23:59:16.967 2010-07-05 00:33:08.107 1726 3212 1428 297
>>>> 4267067 298690 2010-07-05 00:59:15.187 2010-07-05 01:32:48.300 1726 3212 1428 333
>>>> 4270023 298734 2010-07-05 01:59:02.497 2010-07-05 02:32:48.780 1726 3212 1428 270
>>>> 4272977 298778 2010-07-05 02:41:43.737 2010-07-05 03:32:56.043 1726 3212 1428 317
>>>> 4275927 298822 2010-07-05 03:59:17.027 2010-07-05 04:33:14.947 1726 3212 1428 1623
>>>> ================================================================================
>>>>
>>>> Description:
>>>> 1. Column: some ID
>>>> 2. Column: reference to another table
>>>> 3. and 4. column: timestamp from/to of the item
>>>> 5. Column: ID R
>>>> 6. Column: ID L
>>>> 7. Column: ID B
>>>> 8. Column: Sum of components
>>>>
>>>> Requirement:
>>>> Sum over all components (from column 8) for each combination of ID R, ID L, ID B, but (!)
>>>> rows with same keys (R,L,B) should be summed up only until the keys change.
>>>> Do not sum up the components for identical keys, if there are other keys between them.
>>>>
>>>> Example result:
>>>>
>>>> idR idL idB SUM
>>>> 1726 3212 1428 462
>>>> 318 1846 1012 ...
>>>> 1706 3541 1511 ...
>>>> 1726 3212 1428 ...
>>>>
>>>>
>>>> Note that the first and last entry here has the same keys
>>>>
>>>> Maybe you find a similar monster SQL solving such a requirement.
>>>> Thanks for considering!
>>>>
>>>> Rainer
>>>>
>>>>
>>>>
>>>> Am 27.07.2010 12:37, schrieb Oliveiros d'Azevedo Cristina:
>>>>> Howdy, Rainer.
>>>>>
>>>>> It's been a while, so I don't know if you are still interested in this problem or if you, in the meantime, found yourself a solution,
>>>>> but I've tried this on a local copy of the example you provided and it seems to work.
>>>>>
>>>>> The problem is that I suspect that if you have several thousands of records on your table it will become slow...
>>>>>
>>>>> Best,
>>>>> Oliveiros
>>>>>
>>>>> SELECT SUM(tudo.parcela),tudo.a
>>>>> FROM
>>>>> (
>>>>> SELECT fo.parcela,fo.a,fo.b,fo.c,MIN(th.c) as d
>>>>> FROM
>>>>> (
>>>>> SELECT se.a as parcela,se.b as a,se.c as b, MAX(pr.c) as c
>>>>> FROM
>>>>> yourTable se
>>>>> LEFT JOIN
>>>>> (
>>>>> SELECT a.*
>>>>> FROM yourTable a
>>>>> JOIN yourTable b
>>>>> ON (b.b <> a.b)
>>>>> AND ((age(a.c,b.c) = '1 day'::interval)
>>>>>
>>>>> )
>>>>> ) pr
>>>>> ON pr.b = se.b
>>>>> AND se.c >= pr.c
>>>>> GROUP BY se.a,se.b,se.c
>>>>> ) fo
>>>>> LEFT JOIN
>>>>> (
>>>>> SELECT a.*
>>>>> FROM yourTable a
>>>>> JOIN yourTable b
>>>>> ON (b.b <> a.b)
>>>>> AND ((age(a.c,b.c) = '-1 day'::interval)
>>>>> )
>>>>> ) th
>>>>> ON fo.a = th.b
>>>>> AND fo.b <= th.c
>>>>> GROUP BY fo.parcela,fo.a,fo.b,fo.c
>>>>> ) tudo
>>>>> GROUP BY tudo.a,tudo.c,tudo.d
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> To: <pgsql-sql(at)postgresql(dot)org>
>>>>> Sent: Thursday, July 22, 2010 9:09 AM
>>>>> Subject: [SQL] grouping subsets
>>>>>
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> having a table similar to
>>>>>>
>>>>>> | 1 | B | [2010-07-15 Do] |
>>>>>> | 1 | B | [2010-07-16 Fr] |
>>>>>> |---+---+-----------------|
>>>>>> | 2 | C | [2010-07-17 Sa] |
>>>>>> | 2 | C | [2010-07-18 So] |
>>>>>> |---+---+-----------------|
>>>>>> | 1 | B | [2010-07-19 Mo] |
>>>>>> | 1 | B | [2010-07-20 Di] |
>>>>>> | 1 | B | [2010-07-21 Mi] |
>>>>>> | 1 | B | [2010-07-22 Do] |
>>>>>> |---+---+-----------------|
>>>>>> | 3 | D | [2010-07-23 Fr] |
>>>>>>
>>>>>> a simple group by gives me:
>>>>>>
>>>>>> | 6 | B |
>>>>>> | 4 | C |
>>>>>> | 3 | D |
>>>>>>
>>>>>>
>>>>>> What I want to get is the values grouped by "subset", where a subset is a set of rows with identical column until the colum changes.
>>>>>> Is there a way to get
>>>>>>
>>>>>> | 2 | B |
>>>>>> | 4 | C |
>>>>>> | 4 | B |
>>>>>> | 3 | D |
>>>>>>
>>>>>> by SQL only?
>>>>>>
>>>>>> - Rainer
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Sent via pgsql-sql mailing list (pgsql-sql(at)postgresql(dot)org)
>>>>>> To make changes to your subscription:
>>>>>> http://www.postgresql.org/mailpref/pgsql-sql
>>>>>
>>>>>
>>>
>
>