For the request end, you can just use something like:
solrquery.add("group", true);
..etc..
For the response, you have 3 options:
1. specify "group.main=true&group.format=simple" . (note: When I tested this
on a nightly build from back in February I noticed a significant performance
impact from using these params although I imagine the version that is committed
to 3.3 does not have this problem.)
This will return your 1-document-per-group as if it is a regular non-grouped
query and the response will come back just like any other query.
(see the wiki: http://wiki.apache.org/solr/Solrj#Reading_Data_from_Solr
and the javadocs: http://lucene.apache.org/solr/api/overview-summary.html then
scroll to the solrj section.)
2. Full SolrJ support was just added to the 3.x branch so you'll have to use a
nightly build (which ought to be stable & production-quality). See
https://issues.apache.org/jira/browse/SOLR-2637 for more information. After
building the solrj documentation, look for classes that start with "Group"
3. See this posting on how to parse the response "by-hand". This is for a
slightly older version of Field Collapsing than what was committed so it might
not be 100% accurate.
http://www.lucidimagination.com/search/document/148ba23aec5ee2d8/solrquery_api_for_adding_group_filter
James Dyer
E-Commerce Systems
Ingram Content Group
(615) 213-4311
-----Original Message-----
From: Daniel Skiles [mailto:daniel.ski...@docfinity.com]
Sent: Wednesday, August 17, 2011 1:32 PM
To: solr-user@lucene.apache.org
Subject: Re: Return records based on aggregate functions?
Woah. That looks like exactly what I need. Thanks you very much. Is there
any documentation for how to do that using the SolrJ API?
On Wed, Aug 17, 2011 at 2:26 PM, Dyer, James <james.d...@ingrambook.com>wrote:
> Daniel,
>
> This looks like a good usecase for FieldCollapsing (see
> http://wiki.apache.org/solr/FieldCollapsing). Perhaps try something like:
>
> &group=true&group.field=documentId&group.limit=1&group.sort=version desc
>
> James Dyer
> E-Commerce Systems
> Ingram Content Group
> (615) 213-4311
>
>
> -----Original Message-----
> From: Daniel Skiles [mailto:daniel.ski...@docfinity.com]
> Sent: Wednesday, August 17, 2011 1:20 PM
> To: solr-user@lucene.apache.org
> Subject: Return records based on aggregate functions?
>
> I've recently started using Solr and I'm stumped by a problem I'm currently
> encountering. Given that I can't really find anything close to what I'm
> trying to do on Google or the mailing lists, I figured I'd ask if anyone
> here had suggestions on how to do it.
>
> I currently have a schema that looks more or less like this:
>
> uniqueId (string) -- Unique identifier for a record
> documentId (string) -- Id of document represented by this record
> contents (string) -- contents of file represented by this record
> version (float) -- Numeric representation of the version of this document
>
>
> What I'd like to do is submit a query to the server that returns records
> that match against contents, but only if the record has a version field
> that
> is the largest value for all records that share the same documentId.
>
> In other words, I'd like to be able to only search the most recent version
> of a document in some scenarios.
>
> Is this possible with Solr? I'm at an early enough phase that I'm also
> able
> to modify my solr schema if necessary.
>
> Thank you,
> Daniel
>
