PREFIX wikibase: <http://wikiba.se/ontology#>
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX wd: <http://www.wikidata.org/entity/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX bd: <http://www.bigdata.com/rdf#>
# find items that are instances of severe weather
# without dates which could come either from a point in time or a start time property
# but which contain 4-digit number (presumed to be a year) in the item's label in any language

SELECT DISTINCT ?item ?itemLabel ?date WHERE {
  #not sure why adding this initial pattern changes number of results
  ?item wdt:P31 ?type.
  ?type (wdt:P31?/wdt:P279*) wd:Q741507.
  ?item rdfs:label ?humanLabel.

  FILTER NOT EXISTS {
    {?item wdt:P585 ?date}
    UNION
    {?item wdt:P580 ?date}
    }
  FILTER REGEX(?humanLabel,"[0-9]{4}").
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE]","en". }

}

graph TD classDef projected fill:lightgreen; classDef literal fill:orange; classDef iri fill:yellow; v3("?date"):::projected v1("?humanLabel") v2("?item"):::projected v4("?type") a1((" ")) c6(["wd:Q741507"]):::iri c9(["bd:serviceParam"]):::iri c11(["#91;AUTO_LANGUAGE#93;"]):::literal c12(["en"]):::literal f0[["regex(?humanLabel,'#91;0-9#93;{4}')"]] f0 --> v1 f1[["not "]] subgraph f1e0["Exists Clause"] subgraph unione00[" Union "] subgraph unione00l[" "] style unione00l fill:#abf,stroke-dasharray: 3 3; e0v1 --"wdt:P580"--> e0v2 end subgraph unione00r[" "] style unione00r fill:#abf,stroke-dasharray: 3 3; e0v1 --"wdt:P585"--> e0v2 end unione00r <== or ==> unione00l end e0v2("?date"):::projected e0v1("?item"):::projected end f1--EXISTS--> f1e0 f1 --> v2 f1 --> c2 f1 --> v3 f1 --> c3 subgraph union0[" Union "] subgraph union0l[" "] style union0l fill:#abf,stroke-dasharray: 3 3; v2 --"wdt:P580"--> v3 end subgraph union0r[" "] style union0r fill:#abf,stroke-dasharray: 3 3; v2 --"wdt:P585"--> v3 end union0r <== or ==> union0l end v2 --"wdt:P31"--> v4 subgraph union1[" Union "] subgraph union1l[" "] style union1l fill:#abf,stroke-dasharray: 3 3; v4 --"wdt:P31"--> a1 end subgraph union1r[" "] style union1r fill:#abf,stroke-dasharray: 3 3; end union1r <== or ==> union1l end a1 --"wdt:P279"--> c6 v2 --"rdfs:label"--> v1 subgraph s1["http://wikiba.se/ontology#label"] style s1 stroke-width:4px; c9 --"wikibase:language"--> c11 c9 --"wikibase:language"--> c12 end