Is there any function to sum and subtract two numbers (integer or long data types) from two different classes using SPARQL? how to use it ?
As AKSW is suggesting on the comment here it is an example query that adds two variables and projects the result in the total variable.
SELECT ?total
{ ?x ns:itemcount ?xcount .
?y ns:itemcount ?ycount.
BIND (?xcount + ?ycount AS ?total)
}
See SPARQL 1.1 for futher details
Related
Suppose I have the following set of individuals, where some of them have more than one rdfs:label:
Individual
Label
ind_01
"ind-001"
ind_02
"ind-002"
ind_02
"ind-2"
ind_03
"label3"
ind_04
"ind-4"
ind_04
"ind-04"
...
...
I would like to run a SPARQL query that retrieves only one label per individual, no matter which one (i.e., the choice can be totally arbitrary). Thus, a suitable output based on the above dataset would be:
Individual
Label
ind_01
"ind-001"
ind_02
"ind-002"
ind_03
"label3"
ind_04
"ind-4"
...
...
You could use SAMPLE, which "returns an arbitrary value from the multiset passed to it".
SELECT ?individual (SAMPLE(?label) AS ?label_sample)
WHERE {
?individual rdfs:label ?label .
}
GROUP BY ?individual
Suppose I want to look for some first degree neighbors of Berlin. I ask the following query:
select ?s ?p where {
?s ?p dbr:Berlin.
}
Is it possible to put a restriction on the return result, such that there are at most 5 results for each unique value of ?p?
My attempts with subqueries all time out...
But, as potentially useful if not exactly perfect solution, maybe GROUP_CONCAT, MAX/MIN or SAMPLE are of use?
SELECT
?writer (GROUP_CONCAT(?namestring; SEPARATOR = " ") AS ?namestrings)
(MIN(?namestring) AS ?min_name)
(MAX(?namestring) AS ?max_name)
(SAMPLE(?namestring) AS ?random_name)
(SAMPLE(?namestring) AS ?another_random_name_that_may_unfortunately_be_the_same_again)
WHERE {
?writer wdt:P31 wd:Q5;
wdt:P166 wd:Q37922;
wdt:P735 ?firstname.
?firstname wdt:P1705 ?namestring.
}
GROUP BY ?writer
HAVING ((COUNT(?writer)) > 2 )
LIMIT 20
See it live here.
And, as you can see, SAMPLE is apparently evaluated only once, so using it repeatedly does not get you closer to five (different) samples.
(You can leave out the HAVING for your use. I only included it to restrict it to useful examples))
I've been trying to run a sparql query against https://landregistry.data.gov.uk/app/qonsole# to yield some sold properties result.
The query is the following:
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX ukhpi: <http://landregistry.data.gov.uk/def/ukhpi/>
SELECT sum(?ukhpi_salesVolume)
WHERE
{ { SELECT ?ukhpi_refMonth ?item
WHERE
{ ?item ukhpi:refRegion <http://landregistry.data.gov.uk/id/region/haringey> ;
ukhpi:refMonth ?ukhpi_refMonth
FILTER ( ?ukhpi_refMonth >= "2019-03"^^xsd:gYearMonth )
FILTER ( ?ukhpi_refMonth < "2020-03"^^xsd:gYearMonth )
}
}
OPTIONAL
{ ?item ukhpi:salesVolume ?ukhpi_salesVolume }
}
The problem is, the result from this is empty. However, if i run the same query without the SUM on the 4th line, i can see there are 11 integer records.
My thoughts are that there is a 12th, empty record which causes all the issues in the SUM operation, but sparql is not my storngest side so i'm not sure how to filter this (and remove any empty records) if that's really the problem.
I've also noticed that most of the aggregate functions do not work as well(min, max, avg). *Count does, and returns 11
I actually solved this myself, all that was needed was a coalesce which apparently existed in sparql too.
So:
SELECT sum(COALESCE(?ukhpi_salesVolume, 0))
instead of just
SELECT sum(?ukhpi_salesVolume)
This is the query and the result:
As you see, I am filtering out the users that are bo:ania, so why do they still appear?
However, if I remove the widecard and select just the users ?user, bo:ania doesn't appear
I didn't provide a minimum data example because this is a question about how filter and wildcard work, not about a problem in extracting some data from a data set. However, if you need a minimum data, I'm more than happy to provide it.
?specificUser is bound to bo:ania by your VALUES statement. ?user is an entirely different binding defined by the other triple patterns. Your FILTER says to filter out results where ?user = bo:ania, and it appears to be doing that correctly, seeing that ?user is not bound to bo:ania in any of the results.
BTW, there isn't a need to use VALUES in this case unless you want to inspect multiple values. If it's just the one value, then the following would work, and not have you wondering why the binding to bo:ania is included in the result set:
SELECT *
WHERE {
?user a rs:user .
?user rs:hasRated ?rating .
?rating rs:hasRatingDate ?ratngDate .
FILTER (?ratingDates >= (now() -"P10000F"^^xsd:duration) )
FILTER (?user != bo:ania)
}
I am working in DBPedia. I am having a problem when using group by in Sparql.
I have this code:
SELECT ?res ?titulo
WHERE {
?res rdf:type <http://dbpedia.org/class/yago/JaguaresDeChiapasFootballers> .
?res rdfs:label ?titulo .
}
GROUP BY (?res)
LIMIT 15
I want to return a list of all in this type. But I only want to return one for each URI, I put the group by and it doesn’t work and I really don’t know why?
Can someone help me?
Your original query isn't legal SPARQL. If you paste it into the SPARQL query validator at sparql.org, you'll get the following message:
Non-group key variable in SELECT: ?titulo
If you group by ?res, then you can't select the non-group variable ?titulo. If you just want one ?titulo value per ?res, then you can use …
select ?res (sample(?titulo) as ?title)
…
SPARQL results
If you want a list of the titles, then you can use group_concat to concatenate the titles:
select ?res (group_concat(?titulo;separator=', ') as ?title)
…
SPARQL results