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Posted to dev@jena.apache.org by "Rob Vesse (JIRA)" <ji...@apache.org> on 2015/01/13 13:22:34 UTC
[jira] [Comment Edited] (JENA-803) Custom aggregates in SPARQL.
[ https://issues.apache.org/jira/browse/JENA-803?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14275127#comment-14275127 ]
Rob Vesse edited comment on JENA-803 at 1/13/15 12:21 PM:
----------------------------------------------------------
Started updating some code that works with aggregates to test these changes and ran into an interesting bug. An {{AVG(DISTINCT ?x)}} gets turned into a regular {{AVG(?x)}} by the optimiser.
Starting query:
{noformat}
SELECT (COUNT(DISTINCT ?o) AS ?objects) (AVG(DISTINCT ?o) AS ?average) WHERE { ?s ?p ?o }
{noformat}
Raw algebra:
{noformat}
(extend ((?average ?.1))
(extend ((?objects ?.0))
(group () ((?.0 (count distinct ?o)) (?.1 (avg distinct ?o)))
(bgp (triple ?s ?p ?o)))))
{noformat}
Optimised algebra:
{noformat}
(extend ((?objects ?.0) (?average ?.1))
(group () ((?.0 (count distinct ?o)) (?.1 (avg ?o)))
(bgp (triple ?s ?p ?o))))
{noformat}
was (Author: rvesse):
Started updating some code that works with aggregates to test these changes and ran into an interesting bug. An {{AVG(DISTINCT ?x)}} gets turned into a regular {{AVG(?x)}} by the optimiser.
Starting query:
{noformat}
SELECT (COUNT(DISTINCT ?o) AS ?objects) (AVG(DISTINCT ?o) AS ?average) WHERE { ?s ?p ?o }
{/noformat}
Raw algebra:
{noformat}
(extend ((?average ?.1))
(extend ((?objects ?.0))
(group () ((?.0 (count distinct ?o)) (?.1 (avg distinct ?o)))
(bgp (triple ?s ?p ?o)))))
{noformat}
Optimised algebra:
{noformat}
(extend ((?objects ?.0) (?average ?.1))
(group () ((?.0 (count distinct ?o)) (?.1 (avg ?o)))
(bgp (triple ?s ?p ?o))))
{noformat}
> Custom aggregates in SPARQL.
> ----------------------------
>
> Key: JENA-803
> URL: https://issues.apache.org/jira/browse/JENA-803
> Project: Apache Jena
> Issue Type: New Feature
> Components: ARQ
> Affects Versions: Jena 2.12.1
> Reporter: Andy Seaborne
> Assignee: Andy Seaborne
> Fix For: Jena 2.12.2
>
>
> Support SPARQL custom aggregates.
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