Here's an interesting bug. On the DBpedia endpoint, this query:
select ?a ?b ?c where {
values (?a ?b ?c) {
(1 "2" <3>)
("4" <5> 6)
(<7> 8 "9")
}
}
returns these results (CSV here, for clarity):
"a","b","c"
1,,
"4",,
"7",,
There are no values bound for variables ?b and ?c. That said, in the
body of the query, the bindings established by the `values` are in
effect, and certain other parts of the query make bindings appear for
some of the variables. E.g.,
select ?a ?b ?c where {
values (?a ?b ?c) {
(1 "2" <3>)
("4" <5> 6)
(<7> 8 "9")
}
filter(isIRI(?b)) # but ?b will be rendered as a string in the CSV
}
"a","b","c"
"4","5",6
We can't extend that approach to get all the expected results, though:
select ?a ?b ?c where {
values (?a ?b ?c) {
(1 "2" <3>)
("4" <5> 6)
(<7> 8 "9")
}
filter(isIRI(?b))
}
"a","b","c"
"7",,
There's clearly something strange going on here. I ran into this
while answering a StackOverflow question [1], when a user reported
that a solution using `values` didn't work on DBpedia [2] and
illustrated it with a small example, viz.:
select * where { values (?lang ?rank) { ("ru" 1) ("en" 2) } }
//JT
[1] http://stackoverflow.com/q/21531063/1281433
[2]
http://stackoverflow.com/questions/21531063/sparql-multi-lang-data-compression-to-one-row/21531367?noredirect=1#comment32548395_21531367
--
Joshua Taylor, http://www.cs.rpi.edu/~tayloj/
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