Wikidata SPARQL - Countries and their (still existing) neighbours - sparql

Question

I want to query the neighbours to a country with SPARQL from Wikidata like this:
SELECT ?country ?countryLabel WHERE {
?country wdt:P47 wd:Q183 .
FILTER NOT EXISTS{ ?country wdt:P576 ?date } # don't count dissolved country - at least filters German Democratic Republic
SERVICE wikibase:label {
bd:serviceParam wikibase:language "en" .
}
}
My issue is that e.g. in this example for neighbours of germany there are still countries shown which does not exist anymore like:
Kingdom of Denmark or
Saarland.
Already tried
I could already reduce the number by the FILTER statement.
Question
How to make the statement to reduce it to 9 countries?
(also dividing in land boarder and sea boarder would be great)
Alternative
Filtering at this API would be also fine for me https://www.wikidata.org/w/api.php?action=wbgetentities&ids=Q35
a database or lists or prepared HashMaps whatever with all countries of the world with neighbours

Answer 1

You could check entities of type wd:Q133346 ('border') or wd:Q12413618 ('international border'):
SELECT ?border ?borderLabel ?country1Label ?country2Label ?isLandBorder ?isMaritimeBorder ?constraint {
VALUES (?country1) {(wd:Q183)}
?border wdt:P31 wd:Q12413618 ;
wdt:P17 ?country1 , ?country2 .
FILTER (?country1 != ?country2)
BIND (EXISTS {?border wdt:P31 wd:Q15104814} AS ?isLandBorder)
BIND (EXISTS {?border wdt:P31 wd:Q3089219} AS ?isMaritimeBorder)
BIND ((?isLandBorder || ?isMaritimeBorder) AS ?constraint)
SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
} ORDER BY ?country1Label
Try it!
In some sense, records are duplicated: for the Afghanistan–Uzbekistan border, the list contains both (?country1=Afganistan,?country2=Uzbekistan) and (?country1=Uzbekistan,?country2=Afganistan).
a database or lists or prepared HashMaps whatever with all countries of the world with neighbours
You could ask on https://opendata.stackexchange.com.