I removed the graph name projection from the OPTIONAL: PREFIX schema: <https://schema.org/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX sioc: <http://rdfs.org/sioc/ns#>
SELECT DISTINCT ?employee ?reportsToEmployee ?reportsToEmployeeLabel WHERE { GRAPH ?docGraph { ?doc sioc:has_container <https://localhost:4443/employees/> ; foaf:primaryTopic ?employee OPTIONAL { ?employee schema:sponsor ?reportsToEmployee } } OPTIONAL { { SELECT ?reportsToEmployee ?reportsToEmployeeLabel WHERE { { ?reportsToEmployee <http://purl.org/dc/terms/title> ?reportsToEmployeeLabel } UNION { GRAPH ?reportsToEmployeeLabelGraph { ?reportsToEmployee <http://purl.org/dc/terms/title> ?reportsToEmployeeLabel } } } } } } ORDER BY ?doc RDF4J now produces 9 results (same as Dydra), but Fuseki returns 2417 rows. On Tue, Nov 24, 2020 at 3:33 PM Martynas Jusevičius <marty...@atomgraph.com> wrote: > > Yes, it looks like this is due to the different treatment of the named graphs. > > PREFIX schema: <https://schema.org/> > PREFIX foaf: <http://xmlns.com/foaf/0.1/> > PREFIX sioc: <http://rdfs.org/sioc/ns#> > > SELECT (COUNT(?docGraph) AS ?docGraphCount) WHERE { > GRAPH ?docGraph { > ?doc sioc:has_container <https://localhost:4443/employees/>; > foaf:primaryTopic ?employee. > OPTIONAL { ?employee schema:sponsor ?reportsToEmployee. } > } > } > > Dydra: ?docGraphCount = 9 > Fuseki: ?docGraphCount = 9 > RDF4J: ?docGraphCount = 9 > > > PREFIX schema: <https://schema.org/> > PREFIX foaf: <http://xmlns.com/foaf/0.1/> > PREFIX sioc: <http://rdfs.org/sioc/ns#> > > SELECT (COUNT(?reportsToEmployeeLabelGraph) AS > ?reportsToEmployeeLabelGraphCount) WHERE { > GRAPH ?reportsToEmployeeLabelGraph { ?reportsToEmployee > <http://purl.org/dc/terms/title> ?reportsToEmployeeLabel. } > } > > Dydra: ?reportsToEmployeeLabelGraphCount = 2409 > Fuseki: ?reportsToEmployeeLabelGraphCount = 2409 > RDF4J: ?reportsToEmployeeLabelGraphCount = 2409 > > On Tue, Nov 24, 2020 at 3:14 PM Lorenz Buehmann > <buehm...@informatik.uni-leipzig.de> wrote: > > > > It looks more like the cartesian happens on the graphs - how many graph > > do you have matching the first and the second part? > > > > On 24.11.20 14:27, Martynas Jusevičius wrote: > > > Hi, > > > > > > despite using SPARQL for years, cases where different implementations > > > return different results leave me scratching my head. Can someone help > > > me out with this? > > > > > > I have a rather simple query: > > > > > > PREFIX schema: <https://schema.org/> > > > PREFIX foaf: <http://xmlns.com/foaf/0.1/> > > > PREFIX sioc: <http://rdfs.org/sioc/ns#> > > > > > > SELECT * WHERE { > > > GRAPH ?docGraph { > > > ?doc sioc:has_container <https://localhost:4443/employees/>; > > > foaf:primaryTopic ?employee. > > > OPTIONAL { ?employee schema:sponsor ?reportsToEmployee. } > > > } > > > } > > > ORDER BY ?doc > > > > > > Dydra returns 9 results: > > > > > > employee,reportsToEmployee > > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/2/#this, > > > https://localhost:4443/employees/3/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/4/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/5/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/6/#this,https://localhost:4443/employees/5/#this > > > https://localhost:4443/employees/7/#this,https://localhost:4443/employees/5/#this > > > https://localhost:4443/employees/8/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/9/#this,https://localhost:4443/employees/5/#this > > > > > > Fuseki 3.16.0 returns 9 results: > > > > > > employee,reportsToEmployee > > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/2/#this, > > > https://localhost:4443/employees/3/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/4/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/5/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/6/#this,https://localhost:4443/employees/5/#this > > > https://localhost:4443/employees/7/#this,https://localhost:4443/employees/5/#this > > > https://localhost:4443/employees/8/#this,https://localhost:4443/employees/2/#this > > > https://localhost:4443/employees/9/#this,https://localhost:4443/employees/5/#this > > > > > > So far so good -- the results are identical. Now I append an OPTIONAL > > > to the end of the query: > > > > > > PREFIX schema: <https://schema.org/> > > > PREFIX foaf: <http://xmlns.com/foaf/0.1/> > > > PREFIX sioc: <http://rdfs.org/sioc/ns#> > > > > > > SELECT ?employee ?reportsToEmployee ?reportsToEmployeeLabel WHERE { > > > GRAPH ?docGraph { > > > ?doc sioc:has_container <https://localhost:4443/employees/>; > > > foaf:primaryTopic ?employee. > > > OPTIONAL { ?employee schema:sponsor ?reportsToEmployee. } > > > } > > > OPTIONAL { > > > GRAPH ?reportsToEmployeeLabelGraph { ?reportsToEmployee > > > <http://purl.org/dc/terms/title> ?reportsToEmployeeLabel. } > > > } > > > } > > > ORDER BY ?doc > > > > > > Dydra returns 9 results: > > > > > > employee,reportsToEmployee,reportsToEmployeeLabel > > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this,Fuller > > > https://localhost:4443/employees/2/#this,, > > > https://localhost:4443/employees/3/#this,https://localhost:4443/employees/2/#this,Fuller > > > https://localhost:4443/employees/4/#this,https://localhost:4443/employees/2/#this,Fuller > > > https://localhost:4443/employees/5/#this,https://localhost:4443/employees/2/#this,Fuller > > > https://localhost:4443/employees/6/#this,https://localhost:4443/employees/5/#this,Buchanan > > > https://localhost:4443/employees/7/#this,https://localhost:4443/employees/5/#this,Buchanan > > > https://localhost:4443/employees/8/#this,https://localhost:4443/employees/2/#this,Fuller > > > https://localhost:4443/employees/9/#this,https://localhost:4443/employees/5/#this,Buchanan > > > > > > Fuseki 3.16.0 returns 2400+ results: > > > > > > employee,reportsToEmployee,reportsToEmployeeLabel > > > https://localhost:4443/employees/1/#this,https://localhost:4443/employees/2/#this,Fuller > > > https://localhost:4443/employees/2/#this,https://localhost:4443/,Root > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/,Categories > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/1/,Beverages > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/1/#this,Beverages > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/2/,Condiments > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/2/#this,Condiments > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/3/,Confections > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/3/#this,Confections > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/4/,Dairy > > > Products > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/4/#this,Dairy > > > Products > > > https://localhost:4443/employees/2/#this,https://localhost:4443/categories/5/,Grains/Cereals > > > .... > > > > > > Dydra's result is the one I'm going after, and is based on my > > > understanding of OPTIONAL. But is it actually correct? > > > > > > And if Dydra is correct, what is Fuseki doing here? I would have > > > expected the ?reportsToEmployee bindings from the appended OPTIONAL to > > > be joined against the first result (without OPTIONAL), but that is not > > > the case? > > > > > > Thanks. > > > > > > Martynas