Thanks, Andy!
S.
On 10/13/17, 3:40 AM, "Andy Seaborne" <a...@apache.org> wrote:
Thanks.
The inner SELECT isn't really necessary - it is just hiding ?p so rename
that and don't have it in the outer projection:
SELECT ?s ?p ?o
FROM named_graph:m_p
FROM NAMED named_graph:m_p_s
WHERE
{
?s ?p ?o
GRAPH named_graph:m_p_s { ?o ?px w:frnd }
}
Andy
On 13/10/17 11:14, Lorenz Buehmann wrote:
> I answered it on StackOverflow. And the formulation of the question was
> confusing. He probably meant that the subjects of the second graph are
> the object of the first graph. Anything else wouldn't make sense...
>
>
> Here is the data that I used for testing, thus, Andy could also use it:
>
> Graph named_graph:m_p
>
> @prefix : <http://ex.org/> .
> :p1 :pred1 :mp1 .
> :p2 :pred1 :mp1 .
> :p3 :pred1 :mp2 .
> :p4 :pred1 :mp2 .
> :p5 :pred1 :mp3 .
> :p6 :pred1 :mp3 .
>
>
> Graph named_graph:m_p_s
>
> @prefix : <http://ex.org/> .
> @prefix w: <http://ex.org/w/> .
>
> :mp1 :pred2 w:frnd .
> :mp1 :pred2 w:fdlfkdl .
> :mp2 :pred2 w:kdsjflk .
> :mp2 :pred2 w:jflksdlkj .
> :mp3 :pred2 w:frnd .
> :mp3 :pred2 w:fjksldjfls .
>
>
> Working query:
>
> PREFIX named_graph: <http://ex.org/graphs/>
> PREFIX w: <http://ex.org/w/>
>
> SELECT *
> FROM named_graph:m_p
> FROM NAMED named_graph:m_p_s
> WHERE
> {
> ?s ?p ?o
> {
> SELECT ?o WHERE {
> GRAPH named_graph:m_p_s { ?o ?p w:frnd }
> }
> }
> }
>
>
> Cheers,
>
> Lorenz
>
>
>
> On 13.10.2017 10:20, Andy Seaborne wrote:
>>
>>
>> On 13/10/17 02:36, Dimov, Stefan wrote:
>>> Hello,
>>>
>>> I have two graphs:
>>
>> Which storage system are they in?
>> Which version of Jena?
>>
>>>
>>> m_p
>>>
>>> p1 pred1 mp1
>>> p2 pred1 mp1
>>> p3 pred1 mp2
>>> p4 pred1 mp2
>>> p5 pred1 mp3
>>> p6 pred1 mp3
>>>
>>> and m_p_s
>>>
>>> mp1 pred2 w:frnd
>>> mp1 pred2 w:fdlfkdl
>>> mp2 pred2 w:kdsjflk
>>> mp2 pred2 w:jflksdlkj
>>> mp3 pred2 w:frnd
>>> mp3 pred2 w:fjksldjfls
>>
>> Please could you provide complete data such as TriG?
>>
>> It is a barrier to volunteers who answers questions if the first thing
>> you have to do is mangle email, data preparation and disentangle
>> partial queries.
>>
>>> and I want to get all the triples in m_p which objects are predicates
>>> in m_p_s and the object of that predicates in m_p_s is w:frnd
>>>
>>> In other words I want to make query that returns (results with) p1,
>>> p2, p5 and p6 from m_p and doesn’t return p3 and p4.
>>>
>>> I’m trying to do this with nested queries,
>>
>> You don't need a nested SELECT.
>>
>> SELECT * {
>> GRAPH m_p { ?s ?p ?o }
>> GRAPH m_p_s { ?x ?o w:frnd }
>> }
>>
>> (untested)
>>
>>> but it doesn’t work: E.g.
>>>
>>> SELECT $subj $pred $pr
>>
>> $subj and $pred are not set in the query.
>>
>> This isn't SQL! In SPARQL, variables get bound in graph patterns.
>>
>>> FROM NAMED named_graph:m_p
>>
>> The RDF dataset for this query is a single named graph and empty
>> default graph.
>>
>> Did you mean:
>>
>> FROM NAMED named_graph:m_p
>> FROM NAMED named_graph:m_p_s
>>
>> ?
>>
>> or indeed no FROM NAMED and use a dataset directly.
>>
>>
>>> WHERE
>>> {
>>> SELECT $pr
>>> WHERE
>>> {
>>> GRAPH named_graph:m_p_s { $pr $pred0 w:frnd }
>>
>> the m_p_s graph isn't in the dataset hence this pattern is empty.
>>
>> GRAPH is for access; FROM NAMED for setting up.
>>
>>> }
>>> }
>>>
>>> returns empty result. I tried different things, but either I get an
>>> error
>>
>> What is the error?
>>
>>> or empty result or everything in m_p.
>>>
>>> I don’t want to use UNION or FILTER for performance reasons.
>>>
>>> Do you have an idea how I can do it?
>>>
>>> Regards,
>>> Stefan
>>>
>
