Wikidata: How do I ask for the start date of a property in SPARQL?

I have a SPARQL query to Wikidata that returns the names and handles and parties of politicians for whom a Mastodon address is stored at Wikidata. Filtered by nationality and with an output of the name field in the corresponding language.

I would like to extend this so that the start date (P580) of the Mastodon address (P4033) is output in a field in order to be able to sort the result by new members. Does anyone know how to add the question? joinedfediverse should tell the start date.

SELECT ?name ?partyLabel ?mastodon ?joinedfediverse
WHERE {
  ?politician wdt:P31 wd:Q5;                                         # instance of human
             wdt:P106 wd:Q82955;                                     # occupation politician
             wdt:P27 wd:Q183;                                        # country of citizenship Germany
             wdt:P4033 ?mastodon.                                    # Mastodon address
  OPTIONAL {?politician wdt:P580 ?joinedfediverse. }                 # Fediverse joining date
  OPTIONAL {?politician wdt:P39 ?position.                           # position held
            ?position wdt:P279* wd:Q13217683.                        # subclass of member of parliament
            ?position wdt:P1001 ?parliament.}                        # applies to jurisdiction
  OPTIONAL {?politician wdt:P102 ?party.}                            # member of political party
  OPTIONAL {?politician rdfs:label ?name.                            # name
            FILTER(LANG(?name) = "de")}                              # in German language
  SERVICE wikibase:label { bd:serviceParam wikibase:language "de". } # labels in German language
}

posted 4 months ago

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wasuko‭

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