In the examples of the SPARQL of Wikidata, we have this one:
SELECT ?h ?date
WHERE
{
?h wdt:P31 wd:Q5 .
?h wdt:P569 ?date .
OPTIONAL {?h wdt:P570 ?d }
FILTER (?date > "1880-01-01T00:00:00Z"^^xsd:dateTime)
FILTER (!bound(?d))
}
LIMIT 1000
I understand that if you put Label after the name of a variable it shows the label. So, I don't understand why this shows no output:
SELECT ?h ?hLabel ?date ...
Thank you in advance!
I am not aware of that specific feature for Label after the variable name.
However, for rdfs:label, you can to inculde the rdfs:label in your query. Add the following line: ?h rdfs:label ?hLabel.:
SELECT ?h ?hLabel ?date WHERE
{
?h wdt:P31 wd:Q5 .
?h wdt:P569 ?date .
?h rdfs:label ?hLabel.
OPTIONAL {?h wdt:P570 ?d }
FILTER (?date > "1880-01-01T00:00:00Z"^^xsd:dateTime)
FILTER (!bound(?d))
}
LIMIT 1000
If you want labels in a specific language, e.g. for English add FILTER (langMatches( lang(?hLabel), "EN" ) )
Here is a stackoverflow intersting answer about labels.
Related
I wrote the following SPARQL query to find the wikidata item with the label "San Leucio" in Italy.
SELECT DISTINCT * WHERE {
?location ?label 'San Leucio'#en .
?location wdt:P17 wd:Q38 .
?location rdfs:label ?locationName .
OPTIONAL {
?article schema:about ?location .
?article schema:isPartOf <https://en.wikivoyage.org/> .
}
?location wdt:P18 ?image .
FILTER(lang(?locationName) = "en")
}
The query returns these 3 results:
wd:Q55179410
wd:Q20009063
wd:Q846499
The result I want is wd:Q846499, which is outside of Naples, Italy. Is there any way I could further filter this query to return the result that is nearest to Naples? I know that I can get the geoCoordinates for each of these with ?location wdt:P625 ?coordinates, but I'm not sure how I could use that to compare to the geo-coordinates of Naples to get what I want.
SELECT DISTINCT * {
VALUES ?naples {wd:Q2634}
?Napfes wdt:P625 ?naples_coordinates.
?location rdfs:label 'San Leucio'#en .
?location wdt:P17 wd:Q38 .
?location wdt:P18 ?image .
?location wdt:P625 ?location_coordinates.
OPTIONAL {
?article schema:about ?location .
?article schema:isPartOf <https://en.wikivoyage.org/> .
}
BIND (geof:distance(?location_coordinates, ?naples_coordinates) AS ?distance)
} ORDER BY ?distance LIMIT 1
I would like to know how to perform a federated search on GraphDB. For example, to insert the code below in GraphDB, how should I do it? The idea is to add the content below to my local GraphDB.
#Locations of air accidents in wikidata - https://query.wikidata.org/
SELECT ?label ?coord ?place
WHERE
{
?subj wdt:P31 wd:Q744913 .
?subj wdt:P625 ?coord .
?subj rdfs:label ?label
filter (lang(?label) = "en")
}
Posting #UninformedUser's comment as an answer for better readability.
SPARQL 1.1 offers the SERVICE feature, described here. You can use it to perform federated queries against Wikidata directly inside of GraphDB.
SELECT * WHERE {
SERVICE <https://query.wikidata.org/sparql> {
?subj wdt:P31 wd:Q744913 ;
wdt:P625 ?coord ;
rdfs:label ?label
FILTER (lang(?label) = "en")
}
}
To insert the data to your local GraphDB, use something like this:
INSERT {
?subj wdt:P31 wd:Q744913 ;
wdt:P625 ?coord ;
rdfs:label ?label
} WHERE {
SERVICE <https://query.wikidata.org/sparql> {
?subj wdt:P31 wd:Q744913 ;
wdt:P625 ?coord ;
rdfs:label ?label
FILTER (lang(?label) = "en")
}
}
However, you'd probably want to unpack the coordinates and use some ontology that's easier to understand, eg:
PREFIX wgs: <http://www.w3.org/2003/01/geo/wgs84_pos#> # see http://prefix.cc/wgs.sparql
INSERT {
?subj a :AirAccident;
wgs:lat ?lat; wgs:long ?long;
rdfs:label ?label
} WHERE {
SERVICE <https://query.wikidata.org/sparql> {
?subj wdt:P31 wd:Q744913 ;
p:P625/psv:P625 [wikibase:geoLatitude ?lat; wikibase:geoLongitude ?long];
rdfs:label ?label
FILTER (lang(?label) = "en")
}
}
For the p:P625, psv:P625, wikibase:geoLatitude stuff, see https://github.com/nichtich/wdq#wikidata-ontology (and if you install it, wdq help ontology gives this color-coded)
I would like to add a condition to a query, so that, if a result is empty, it fills it with a result of another query.
For example : If a owl:Class has no "skos:definition", I would like to replace it by a "rdfs:comment"
Is this possible ?
Thank you !
COALESCE is can help, especially as you get more choices from skos:prefLabel, skos:altLabel and more.
OPTIONAL { ?property rdfs:label ?label }
OPTIONAL { ?property skos:definition ?definition .}
# ... other ways to choose ?comment ...
BIND ( COALESCE(?definition, ?label, "Unknown") AS ?comment )
COALESCE allows expressions (unlike BOUND)
https://www.w3.org/TR/sparql11-query/#func-coalesce
I found something with BIND (IF(BOUND(...) ..., ...) AS ...) statement.
SELECT DISTINCT ?type ?property ?comment ?propertyType ?domain
WHERE {
?property rens:hasAttributeType ?propertyType .
?property rens:hasForDomain ?domain .
?property rdf:type ?type .
?property rdfs:label ?label .
OPTIONAL {?property skos:definition ?definition .}
BIND(IF(BOUND(?definition), ?definition, ?label) AS ?comment) .
}
Is this the better way ?
I'm developing my own Fuseki endpoint from some DBpedia data.
I'm in doubt on how to aggregate properties related to a single resource.
SELECT ?name ?website ?abstract ?genre ?image
WHERE{
VALUES ?s {<http://dbpedia.org/resource/Attack_Attack!>}
?s foaf:name ?name ;
dbo:abstract ?abstract .
OPTIONAL { ?s dbo:genre ?genre } .
OPTIONAL { ?s dbp:website ?website } .
OPTIONAL { ?s dbo:image ?image } .
FILTER LANGMATCHES(LANG(?abstract ), "en")
}
SPARQL endpoint: http://dbpedia.org/sparql/
This query returns 2 matching results. They are different just for the dbo:genre value. There is a way I can query the knowledge base and retrieving a single result with a list of genres?
#chrisis's query works well on the DBpedia SPARQL Endpoint, which is based on Virtuoso.
However, if you are using Jena Fuseki, you should use more conformant syntax:
PREFIX dbo: <http://dbpedia.org/ontology/>
PREFIX dbp: <http://dbpedia.org/property/>
SELECT
?name
(SAMPLE(?website) AS ?sample_website)
(SAMPLE(?abstract) AS ?sample_abstract)
(SAMPLE(?image) AS ?sample_image)
(GROUP_CONCAT(?genre; separator=', ') AS ?genres)
WHERE {
VALUES (?s) {(<http://dbpedia.org/resource/Attack_Attack!>)}
?s foaf:name ?name ;
dbo:abstract ?abstract .
OPTIONAL { ?s dbo:genre ?genre } .
OPTIONAL { ?s dbp:website ?website } .
OPTIONAL { ?s dbo:image ?image} .
FILTER LANGMATCHES(LANG(?abstract ), "en")
} GROUP BY ?name
The differences from the #chrisis's query are:
Since GROUP_CONCAT is an aggregation function, it might be used with GROUP BY only;
Since GROUP BY is used, all non-grouping variables should be aggregated (e.g. via SAMPLE);
GROUP_CONCAT syntax is slightly different.
In Fuseki, these AS in the projection are in fact superfluous: see this question and comments.
Yes, the GROUP_CONCAT() function is what you want.
SELECT ?name ?website ?abstract (GROUP_CONCAT(?genre,',') AS ?genres) ?image
WHERE{
<http://dbpedia.org/resource/Attack_Attack!> a dbo:Band ;
foaf:name ?name;
dbo:abstract ?abstract .
OPTIONAL{ <http://dbpedia.org/resource/Attack_Attack!> dbo:genre ?genre } .
OPTIONAL{ <http://dbpedia.org/resource/Attack_Attack!> dbp:website ?website} .
OPTIONAL{ <http://dbpedia.org/resource/Attack_Attack!> dbo:image ?image} .
FILTER LANGMATCHES(LANG(?abstract ), "en")
}
I am not very used to SPARQL, but I managed to write my own query for books and their genres, authors and their dates of birth and death at https://query.wikidata.org
SELECT
?title ?titleLabel
(GROUP_CONCAT(DISTINCT(?authorLabel); separator="//") as ?authors)
(GROUP_CONCAT(DISTINCT(?dateborn); separator="//") as ?date_born)
(GROUP_CONCAT(DISTINCT(?datedeath); separator="//") as ?date_death)
(GROUP_CONCAT(DISTINCT(?datepub); separator="//") as ?date_pub)
(GROUP_CONCAT(DISTINCT(?genre_titleLabel); separator="//") as ?genre_title)
WHERE
{
?title wdt:P31 wd:Q571 .
?title wdt:P50 ?author .
?title wdt:P577 ?date_pub .
?author wdt:P569 ?date_born .
?author wdt:P570 ?date_death .
?title wdt:P136 ?genre_title .
BIND(CONCAT(STR(DAY(?date_pub)),"-",STR(MONTH(?date_pub)),"-",STR(YEAR(?date_pub))) AS ?datepub )
BIND(CONCAT(STR(DAY(?date_born)),"-",STR(MONTH(?date_born)),"-",STR(YEAR(?date_born))) AS ?dateborn )
BIND(CONCAT(STR(DAY(?date_death)),"-",STR(MONTH(?date_death)),"-",STR(YEAR(?date_death))) AS ?datedeath )
FILTER (?date_born > "1900-01-01T00:00:00Z"^^xsd:dateTime) .
FILTER (?date_born < "1905-12-31T23:59:59Z"^^xsd:dateTime)
SERVICE wikibase:label {
bd:serviceParam wikibase:language "en" .
?title rdfs:label ?titleLabel .
?author rdfs:label ?authorLabel .
?date_pub rdfs:label ?date_pubLabel .
?date_born rdfs:label ?date_bornLabel .
?date_death rdfs:label ?date_deathLabel .
?genre_title rdfs:label ?genre_titleLabel .
}
}
GROUP BY ?title ?titleLabel
It works and I get all the genres in the same field. The only way I could get this was with
(GROUP_CONCAT(DISTINCT(
for genres and dates. But If you loook in the results there are records with more than one date. And I want to get only the first date, and not all the stored dates in the database for this record, but I can't.
For example, If I ask for
?dateborn
instead of
(GROUP_CONCAT(DISTINCT(?dateborn); separator="//") as ?date_born)
I get an error. Do you know where is my mistake?
Greets
N.