On 6/28/2010 8:12 AM, Sergio Fernández wrote:
Hi,
I wonder if anyone knows how can I write a single SPARQL query to
retrieve all triples with the same triple pattern without post-process
the query result.
Let's put an example: using FOAF is quite common to have a dataset like:
#person1 foaf:name "Person1" .
#person1 foaf:knows #person2 .
#person1 foaf:knows #person3 .
...
#person1 foaf:knows #personN .
How can I get all knows for a concrete subject? And I'd like to do it
just with SPARQL in a single query. So the two ways that I know:
1. Post-process the query's result, merging result about the same subject
2. Perform two queries: one for the single properties, and a second
for the multivalued stuff.
are not valid at all. Anyone has any another idea...?
Thanks in advance.
Kind regards,
Hi Sergio,
I think you are saying that you require a single row per subject, but
want all of the foaf:knows for that subject within that single solution.
You can't do this in SPARQL 1.0 without post-processing. You will be
able to do it in SPARQL 1.1 with the GROUP_CONCAT aggregate:
SELECT ?person (GROUP_CONCAT(?knows) AS ?knows_string)
WHERE
{
?person foaf:knows ?knows
}
GROUP BY ?person
Lee
