Wikidata/SPARQL, get distinct items (object id) in result - sparql

Question

When I run the following query I get multiple rows of "Paul Gauguin" since there are multiple informations about his place/time of death, the same could of course happen on all other parameters as well.
SELECT DISTINCT ?item ?itemLabel ?itemDescription ?birthplaceLabel ?birthdate ?deathplaceLabel ?deathdate ?imageLabel ?article ?articleEn
{
?item wdt:P31 wd:Q5.
?item wdt:P119 wd:Q5024152.
OPTIONAL {
?item wdt:P18 ?image.
}
OPTIONAL {
?item wdt:P19 ?birthplace.
}
OPTIONAL {
?item wdt:P569 ?birthdate.
}
OPTIONAL {
?item wdt:P20 ?deathplace.
}
OPTIONAL {
?item wdt:P570 ?deathdate.
}
OPTIONAL {
?article schema:about ?item.
?article schema:isPartOf <https://sv.wikipedia.org/>.
}
OPTIONAL {
?articleEn schema:about ?item.
?articleEn schema:isPartOf <https://en.wikipedia.org/>.
}
SERVICE wikibase:label { bd:serviceParam wikibase:language "sv,en, [AUTO_LANGUAGE]". }
}
Is there a way of only recive one of the same object id, and don't care about if there are other "versions" of the object.
I have tried a bit with nested queries but I can't get it to work. Are there som other ways?

Answer 1

This query will work:
SELECT DISTINCT ?item ?itemLabel ?itemDescription
(SAMPLE(?birthplaceLabel) AS ?birthplaceLabel)
(SAMPLE(?birthdate) AS ?birthdate)
(SAMPLE(?deathplaceLabel) AS ?deathplaceLabel)
(SAMPLE(?deathdate) AS ?deathdate)
(SAMPLE(STR(?image)) AS ?image)
?article ?articleEn
WHERE {
?item wdt:P31 wd:Q5.
?item wdt:P119 wd:Q5024152.
OPTIONAL {
?item wdt:P18 ?image.
}
OPTIONAL {
?item wdt:P19 ?birthplace.
}
OPTIONAL {
?item wdt:P569 ?birthdate.
}
OPTIONAL {
?item wdt:P20 ?deathplace .
}
OPTIONAL {
?item wdt:P570 ?deathdate.
}
OPTIONAL {
?article schema:about ?item.
?article schema:isPartOf <https://sv.wikipedia.org/>.
}
OPTIONAL {
?articleEn schema:about ?item.
?articleEn schema:isPartOf <https://en.wikipedia.org/>.
}
SERVICE wikibase:label { ?birthplace rdfs:label ?birthplaceLabel .
?deathplace rdfs:label ?deathplaceLabel .
?item rdfs:label ?itemLabel ;
schema:description ?itemDescription .
bd:serviceParam wikibase:language "sv,en, [AUTO_LANGUAGE]". }
}
GROUP BY ?item ?itemLabel ?itemDescription ?article ?articleEn
As you can see, we use the SAMPLE function and group by all the variables that aren't sampled.
You could also replace SAMPLE with GROUP_CONCAT if you wish to see all the possible values taken by a property.
E.g. ... (GROUP_CONCAT(?deathdate; SEPARATOR="; ") AS ?deathdates) ...
Note that GROUP_CONCAT takes strings as arguments.

Answer 2

Found the solution with a bit of modyfing of Valerio Cocchis answer.
SELECT ?item ?itemLabel ?itemDescription
(SAMPLE(?birthplaceLabel) AS ?birthplaceLabel)
(SAMPLE(?birthdate) AS ?birthdate)
(SAMPLE(?deathplaceLabel) AS ?deathplaceLabel)
(SAMPLE(?deathdate) AS ?deathdate)
(SAMPLE(?imageLabel) AS ?imageLabel)
?article ?articleEn
WHERE {
?item wdt:P31 wd:Q5.
?item wdt:P119 wd:Q5024152.
OPTIONAL {
?item wdt:P18 ?image.
}
OPTIONAL {
?item wdt:P19 ?birthplace.
}
OPTIONAL {
?item wdt:P569 ?birthdate.
}
OPTIONAL {
?item wdt:P20 ?deathplace.
}
OPTIONAL {
?item wdt:P570 ?deathdate.
}
OPTIONAL {
?article schema:about ?item.
?article schema:isPartOf <https://sv.wikipedia.org/>.
}
OPTIONAL {
?articleEn schema:about ?item.
?articleEn schema:isPartOf <https://en.wikipedia.org/>.
}
SERVICE wikibase:label {
bd:serviceParam wikibase:language "sv,en, [AUTO_LANGUAGE]".
?birthplace rdfs:label ?birthplaceLabel .
?deathplace rdfs:label ?deathplaceLabel .
?image rdfs:label ?imageLabel .
?item rdfs:label ?itemLabel .
?item schema:description ?itemDescription .
}
}
GROUP BY ?item ?itemLabel ?itemDescription ?article ?articleEn