The following Wikidata query returns a list of airports and their IATA codes.
I am using ?airport rdfs:label ?airportName to also get a label for the airports. Most airports have labels in multiple languages, so I want to select preferably the english name. Some airports have only the language en-ca and en-gb, but not en, so I cannot select them with lang(?airportName) = 'en'.
With the current implementation, I get multiple records for some airports:
select
?airport
?airportName
(lang(?airportName) as ?lang)
?IATAAirPortCode
{
?airport
wdt:P238
?IATAAirPortCode
optional {?airport rdfs:label ?airportName .
filter(langMatches(lang(?airportName), 'en')) }
}
order by
?IATAAirPortCode
I'd like to have one record per airport only. Is it somehow possible to formulate an optional { ... } clause to return at most one record of an airport.
For this style of query where you want a single rdfs:label value per result, you can use wikidata's wikibase:label SPARQL extension like this:
SELECT
?airport
?airportLabel
(LANG(?airportLabel) AS ?lang)
?IATAAirPortCode
{
?airport wdt:P238 ?IATAAirPortCode
SERVICE wikibase:label {
bd:serviceParam wikibase:language "en"
}
}
ORDER BY ?IATAAirPortCode
The ?airportLabel variable is automatically bound to the label of each ?airport with only labels in the given preferred language (the language string "en" here can contain multiple, comma-separated acceptable language codes).
A more general-purpose solution that is portable SPARQL (without wikidata extensions) would be more complicated, and might differ depending on the specifics of the query. In this particular case, where your OPTIONAL is only adding one variable, you can do it without using the wikibase extension by using GROUP BY and SAMPLE aggregation:
SELECT
?airport
(SAMPLE(?airportLabel) AS ?airportName)
(LANG(?airportName) AS ?lang)
?IATAAirPortCode
{
?airport wdt:P238 ?IATAAirPortCode
OPTIONAL {
?airport rdfs:label ?airportLabel
FILTER(langMatches(lang(?airportLabel), 'en'))
}
}
GROUP BY ?airport ?IATAAirPortCode
ORDER BY ?IATAAirPortCode
Related
I'm trying to pull the wikidata description of biblical figures.
For example, for David, this would pull: king of Israel and Judah.
Here's what I started with:
select ?person ?personLabel
where {
?person wdt:P31 wd:Q20643955.
SERVICE wikibase:label {
bd:serviceParam wikibase:language "en" .
}
}
From Wikidata Query Service/User Manual § Label_service:
You can fetch the label, alias, or description [...] In automatic mode, you only need to specify the service template, e.g.:
PREFIX wikibase: <http://wikiba.se/ontology#>
SERVICE wikibase:label {
bd:serviceParam wikibase:language "en" .
}
and WDQS will automatically generate labels as follows:
If an unbound variable in SELECT is named ?NAMELabel, then WDQS produces the label (rdfs:label) for the entity in variable ?NAME.
If an unbound variable in SELECT is named ?NAMEAltLabel, then WDQS produces the alias (skos:altLabel) for the entity in variable
?NAME.
If an unbound variable in SELECT is named ?NAMEDescription, then WDQS produces the description (schema:description) for the
entity in variable ?NAME.
So you can just specify ?personDescription among your selected variables.
Here an example.
I have a SPARQL query where I try to retrieve all current german municipalities from wikidata, with some of their properties.
For example I try to retrieve their postal codes and parent regions:
SELECT DISTINCT ?region ?regionLabel ?postalCode ?parentLabel WHERE {
?region wdt:P31 wd:Q262166. # Municipalities
?region wdt:P17 wd:Q183. # from Germany
MINUS { ?region p:P576 _:anyValue. } # Only regions which exist today
OPTIONAL { ?region wdt:P281 ?postalCode. } # Select postal code
OPTIONAL { ?region wdt:P131 ?parent. } # Select administrative parents
SERVICE wikibase:label { bd:serviceParam wikibase:language "de" . } # Show german labels
}
As you can seen, I already found out how to exclude those municipalities which doesn't exist any more (because they have a property p:P576 = end date). I know it is a little bit fuzzy, because it could be an end date in the future (which is only determined already).
But more important, the postal codes and parents include "historical ones", which I would like to exclude. I know that I could do something like answered in "https://stackoverflow.com/questions/49066390/how-to-get-only-the-most-recent-value-from-a-wikidata-property", but the solution their is to bind the end date of the properties, which is usually not set for the current value. Despite the fact that I don't know how to build the query with two optional values.
I want to write a SPARQL query that would return the first name of a person based on the ranking of the name on Wikidata.
For example, let's say I want the second first name of Mozart (Chrysostom).
This is what I have so far (Mozart Wikidata ID is Q254, first name's property is P735, with P1545 giving the ordinal position of the name):
SELECT DISTINCT ?full_name ?full_nameLabel ?first_nameLabel ?rank
WHERE
{
VALUES ?full_name {wd:Q254} .
?full_name p:P735 [pq:P1545 ?rank] ;
p:P735 [ps:P735 ?first_name] ;
FILTER regex(?rank, "2")
SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}
However here the filter only applies to the rank variable, and not on the first_name variable:
Query result:
I think that the problem comes from the fact that the rank property is a sub-element of the first_name property. Would you know of a way to filter the first_name variable by the rank variable?
SELECT DISTINCT ?id ?idLabel ?first_nameLabel ?rank
WHERE {
VALUES ?id {wd:Q254} .
?id p:P735 [
pq:P1545 ?rank;
ps:P735 ?first_name
]
FILTER(?rank = "2")
SERVICE wikibase:label { bd:serviceParam wikibase:language "en" }
}
I'd like to ask one tricky thing about label. Using SERVICE keyword like SERVICE wikibase:label { bd:serviceParam wikibase:language "ko,en". } enable us to switch language label when the first preference is not mached to the target entity label.
However, I want to drop out some entities that does not have any label. However, the service keyword add entity with Qxxxx label when the entity does not have any language match label. How could I remove the entity from the result?
I know we can filter that out using rdfs:label for the all the variables explicitly but setting all the rdfs:label to all the variables is another headeache. So I'd like to know how to improve the query with SERVICE wikibase:label I want to filter out entity that doesn't have any label. Should I replace SERVICE with rdfs:label?
SELECT DISTINCT ?vLabel
WHERE {
hint:Query hint:optimizer "None" .
{
SELECT DISTINCT ?i {
?i wdt:P31 wd:Q515.
}LIMIT 15
}
?v wdt:P937 ?i.
SERVICE wikibase:label { bd:serviceParam wikibase:language "ko,en". }
}
LIMIT 3
RESULT:
Q59780594 <- no lang label
Q24642253 <- no lang label
The Wikidata label service doesn't provide a built-in way to skip resources that don't have a label.
The simplest option would be to wrap the query as a subquery into a new SELECT query, and use a filter to remove any Qxxxx labels. This uses the fact that only the real labels have a language tag:
SELECT ?vLabel {
{
SELECT DISTINCT ?vLabel
...
}
FILTER lang(?vLabel)
}
Edit: Below is my original (and inferior) answer, which used a regular expression on the label itself to remove the Qxxxx ones. It would also filter out any resources that actually have a label of the form Qxxxx, if such resources exist in Wikidata.
SELECT ?vLabel {
{
SELECT DISTINCT ?vLabel
...
}
FILTER (!REGEX(?vLabel, "^Q[0-9]+$"))
}
I am trying to return results for a set of persons (Edinburgh University alumni) who have held political office. I would like to return the title label of the office held, along with the start and end dates for each office, with many individuals holding multiple positions. I seem to be able to get one or the other or can get it to work if the person only held one position, but can't get the two to come together where multiple offices were held.
My current version of the query is below. This will give me the start and end dates, but rather than the label if the political office, such as Member of the [x] Parliament of the United Kingdom, ?officeLabel returns a value such as: statement/Q4668868-E3734C7D-40F0-4D4A-8208-E3D6B8C944CB
SELECT DISTINCT ?alumni ?fullName ?roleLabel ?officeLabel ?start ?end WHERE {
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
?alumni wdt:P69 wd:Q160302.
?alumni rdfs:label ?fullName.
?alumni wdt:P106 ?role.
#Use Values to separate out politicians - Q82955
VALUES (?role) {
(wd:Q82955)
}
#Select only where position of office is stated but make dates optional
?alumni p:P39 ?office.
OPTIONAL { ?office pq:P580 ?start. }
OPTIONAL { ?office pq:P582 ?end. }
FILTER(LANGMATCHES(LANG(?fullName), "en"))
FILTER(NOT EXISTS { FILTER(LANGMATCHES(LANG(?fullName), "en-ca")) })
FILTER(NOT EXISTS { FILTER(LANGMATCHES(LANG(?fullName), "en-gb")) })
}
ORDER BY ?fullName
LIMIT 10
Yeah, I still get tripped up on qualifiers and the Wikidata Data Model too.
Diagram by
By Michael F. Schönitzer - Own work, based on File:Rdf mapping.svg, CC
BY 4.0, https://commons.wikimedia.org/w/index.php?curid=63880194
After going the "p: route" from the "item", you need the "ps: route" to get back to the "simple value".
So, using this to slightly modify your query gives the results I think you want.
SELECT DISTINCT ?alumni ?fullName ?roleLabel ?officeLabel ?start ?end WHERE {
?alumni wdt:P69 wd:Q160302.
?alumni rdfs:label ?fullName.
?alumni wdt:P106 ?role.
VALUES (?role) {
(wd:Q82955)
}
?alumni p:P39 ?officeStmnt.
?officeStmnt ps:P39 ?office.
OPTIONAL { ?officeStmnt pq:P580 ?start. }
OPTIONAL { ?officeStmnt pq:P582 ?end. }
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
FILTER(LANGMATCHES(LANG(?fullName), "en"))
FILTER(NOT EXISTS { FILTER(LANGMATCHES(LANG(?fullName), "en-ca")) })
FILTER(NOT EXISTS { FILTER(LANGMATCHES(LANG(?fullName), "en-gb")) })
}
ORDER BY ?fullName
LIMIT 10
Link to query on Wikidata