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From Ryan Ramage <ryan.ram...@gmail.com>
Subject Re: how to sum values of a view in a date range?
Date Thu, 09 Jun 2011 17:25:50 GMT
As a side note, pairing the _stats function with jstat
[http://www.jstat.org/] is a nice and easy way to graph min, max,
average and std.

Here is an example:
http://pastebin.com/3yU3Ncy8

On Thu, Jun 9, 2011 at 11:12 AM, Robert Newson <robert.newson@gmail.com> wrote:
> Average isn't going to be possible without introducing compound
> rounding errors (which, in my opinion, render the results useless).
>
> The suggestion to use _stats sounded right to me. That will give you
> both the count of items and the sum of those items, perform the final
> (single) division in the client to avoid compound rounding errors.
>
> B.
>
> On 9 June 2011 18:04, Sean Copenhaver <sean.copenhaver@gmail.com> wrote:
>> Yowza, I missed a lot in this thread. Yeah I thought you needed sum, but I
>> provided a lot of examples of querying with some test data on your
>> stackoverflow question. I hope that helps. It would actually be nice to see
>> a built in _avg reduce function though.
>>
>>
>> On Thu, Jun 9, 2011 at 12:39 PM, Robert Newson <robert.newson@gmail.com>wrote:
>>
>>> One minor point, your documents won't sort correctly (and therefore
>>> your sums will be wrong). A string of this form "[2011, 6, 7, 10, 55]"
>>> will not sort the same as the array you intended [2011, 6, 7, 10, 55].
>>>
>>> B.
>>>
>>> On 9 June 2011 17:36, Fabio Di Bernardini <fdb@altraqua.com> wrote:
>>> > I need to make a chart with hourly sum of values restricted to March. So
>>> I
>>> > don't need one number with the sum of whole March month.
>>> >
>>> >
>>> > 2011/6/9 David Hardtke <david@cloudant.com>
>>> >
>>> >> Hi Fabio,
>>> >>
>>> >> This should work.  You can use the _sum builtin as reduce:
>>> >>
>>> >> "reduce":"_sum"
>>> >>
>>> >> You then need to query your view with the proper group level and a
>>> startkey
>>> >> and endkey:
>>> >>
>>> >> GET
>>> >>
>>> db/_design/power/_view/watt?group_level=2&startkey=[2011,3]&endkey=[2011,4]&inclusive_end=false
>>> >>
>>> >> That gives you the sum for the month of March.
>>> >>
>>> >>
>>> >>
>>> >>
>>> >> On 06/09/11 09:06, Fabio Di Bernardini wrote:
>>> >>
>>> >>> Il 09/06/2011 17:18, Fabio Di Bernardini ha scritto:
>>> >>>
>>> >>>> If I have a map function emitting a timestamp as key ad a number
as
>>> >>>> document, how to get sum of values selecting a date range?
>>> >>>>
>>> >>>
>>> >>> More datails here:
>>> >>>
>>> >>>
>>> http://stackoverflow.com/questions/6294794/how-to-sum-values-of-a-view-in-a-date-range-using-couchdb
>>> >>>
>>> >>
>>> >>
>>> >
>>>
>>
>>
>>
>> --
>> “The limits of language are the limits of one's world. “ -Ludwig von
>> Wittgenstein
>>
>



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