Dear all,
I have to write a query where I
1) want to select some entities with a subquery S, let's call the result set R
2) take the crossproduct R x R, and
3) apply some filter on R x R
Below you find a working query like that, acting on some gene data.
The crucial point for me is: In order to obtain R x R, I use the subquery S
twice.
This is something I don't like: Not-so-smart SPARQL processors would run the
subquery twice, though theoretically, it would be sufficient to run S only once,
if there was an easy way to "construct" from the result set R the cross-product
R X R.
So my question is: Is there a better way to write that query without running S
twice?
Is there a convenient way to let SPARQL generate R x R, when there is a SPARQL
query
which generates R?
Best
Frithjof
select ?gene1 (concat(">= ",xsd:string(?cdetected2)," detected") as ?o1)
where
{
{
#
# subquery S, first instance
#
select (?gene as ?gene1) (count(?ta1) as ?cdetected1)
where
{
?gene a :Gene .
?ta1 a :Textual_Annotation .
?ta1 :has_involved_gene ?gene .
?ta1 :has_strength :level_detected .
}
GROUP BY ?gene
ORDER BY DESC(?cdetected1)
LIMIT 5
}
{
#
# subquery S, second instance
#
select (?gene as ?gene2) (count(?ta1) as ?cdetected2)
where
{
?gene a :Gene .
?ta1 a :Textual_Annotation .
?ta1 :has_involved_gene ?gene .
?ta1 :has_strength :level_detected .
}
GROUP BY ?gene
ORDER BY DESC(?cdetected2)
LIMIT 5
}
#
# filter condition on R X R
#
FILTER (?cdetected1>=?cdetected2)
}
Dr. Frithjof Dau
Senior Researcher, Business Intelligence Practice I SAP Research Dresden
SAP AG I Chemnitzer Str. 48 I 01187 Dresden I Germany
T +49 351 4811-6152 I F +49 6227 78-51425 I mailto:
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