Get one document from each category

[Tomasz Kępski <to...@kepski.pl>]

Hi,

I have the following case:

In my index I do have documents categorized (category_id - int sortable 
field). I would like to get three top documents matching user query BUT 
each have to be from different category.:

for example from returned set (doc_id : category id):

1:1
2:1
3:1
4:2
5:1
6:2
7:3
8:4

I would like to get docs 1, 4 and 7.
Is that possible without quering 3 times? Often lot of (more than my 
limit) the docs at the beginning are from the same category.
I'm using PHP Apache Solr so I would like to avoid processing large sets 
of data in my PHP based application.

Tomek

Re: Get one document from each category

[Andrey Klochkov <ak...@griddynamics.com>]

Hi

I think you need field collapsing, look here

http://wiki.apache.org/solr/FieldCollapsing

2009/11/24 Tomasz Kępski <to...@kepski.pl>

> Hi,
>
> I have the following case:
>
> In my index I do have documents categorized (category_id - int sortable
> field). I would like to get three top documents matching user query BUT each
> have to be from different category.:
>
> for example from returned set (doc_id : category id):
>
> 1:1
> 2:1
> 3:1
> 4:2
> 5:1
> 6:2
> 7:3
> 8:4
>
> I would like to get docs 1, 4 and 7.
> Is that possible without quering 3 times? Often lot of (more than my limit)
> the docs at the beginning are from the same category.
> I'm using PHP Apache Solr so I would like to avoid processing large sets of
> data in my PHP based application.
>
> Tomek
>



-- 
Andrew Klochkov
Senior Software Engineer,
Grid Dynamics