sparql_meta_queries.md

Adapted from Sparql Playground and other sources

Add the following prefixes or others to the queries as needed

PREFIX  rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX owl:  <http://www.w3.org/2002/07/owl#>

what the data look like?

SELECT * WHERE {?subject ?predicate ?object . }
LIMIT 10

How many triples in the dataset?

SELECT (COUNT(*) AS ?no)  WHERE { ?s ?p ?o  }

What classes are defined?

SELECT distinct ?class
WHERE { {?class a rdfs:Class} UNION {?class a owl:Class} }
order by ?class

Number of immediate instances of class XXX

SELECT (COUNT(?s) AS ?totalNumberOfInstances)
WHERE { ?s a XXX}

Number of immediate or indirect instances of class XXX

SELECT (COUNT(?s) AS ?totalNumberOfInstances)
WHERE { ?s rdfs:type/rdfs:subclassOf* XXX}

Number of immediate instances of all classes

SELECT ?class (count(?instance) as ?numberOfInstances)
WHERE { ?instance a ?class . }
group by ?class
order by desc(?numberOfInstances)

What properties are used?

SELECT DISTINCT ?property
WHERE { ?s ?property ?o . }

Which classes use property XXX?

SELECT DISTINCT ?class
WHERE {
    ?subject XYZZY ?o .
    ?subject a ?class . }

How often is a property XXX used

SELECT (COUNT(*) AS ?total)
WHERE { ?s XXX ?o }

How often has each property been used?

SELECT ?property (COUNT(?property) AS ?propTotal)
WHERE { ?s ?property ?o . }
GROUP BY ?property
ORDER BY DESC(?propTotal)