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SPARQL

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psweatte edited this page Jul 6, 2020 · 26 revisions

WikiData Query Autocomplete Documentation

  1. Prefix words with "?" to autocomplete subjects
  2. Prefix words with "wdt:" or "wd:" to autocomplete objects

Flow

select alexa rank > 500; get website where alexa > 500

Syntax

# Demonstrates filtering for value greater than a real number
SELECT DISTINCT ?alexarank ?website ?websiteLabel ?sitelink 
WHERE
{
?website wdt:P1661 ?alexarank.
    OPTIONAL{ ?website wdt:P856 ?sitelink }
FILTER (?alexarank < 200) .
SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en" }
}
ORDER BY ?alexarank

URL

https://query.wikidata.org/#%23%20Demonstrates%20filtering%20for%20value%20greater%20than%20a%20real%20number%0ASELECT%20DISTINCT%20%3Falexarank%20%3Fwebsite%20%3FwebsiteLabel%20%3Fsitelink%20%0AWHERE%0A%7B%0A%09%3Fwebsite%20wdt%3AP1661%20%3Falexarank.%0A%20%20%20%20OPTIONAL%7B%20%3Fwebsite%20wdt%3AP856%20%3Fsitelink%20%7D%0A%09FILTER%20%28%3Falexarank%20<%20200%29%20.%0A%09SERVICE%20wikibase%3Alabel%20%7B%20bd%3AserviceParam%20wikibase%3Alanguage%20"%5BAUTO_LANGUAGE%5D%2Cen"%20%7D%0A%7D%0AORDER%20BY%20%3Falexarank

Cheatsheets

Endpoints

Conceptually, we are SELECTing a list of attributes FROM a set of tables WHERE certain constraints are met. These constraints capture the relationships implicit in the scheme, Person.addr=Addresses.ID, and the selection criteria, e.g. Address.state=”MA”.

A SPARQL query of the same data could look like

SELECT ?name ?city
WHERE {
?who <Person#fname> ?name ;
<Person#addr> ?adr .
?adr <Address#city> ?city ;
<Address#state> “MA”
}


SELECT ?reaction ?p ?o
WHERE {
?compound ex:name “illudium phosdex” ;
?reaction ex:involves ?compound ;
?reaction ?p ?o
}

In SQL, this would be like:

SELECT reactions.*
FROM reactions, compounds
WHERE reactions.compoundID=compounds.ID
AND compounds.name=”illudium phosdex”

Games

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