“or” in a SPARQL query

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野趣味
野趣味 2021-02-02 09:35

I don\'t quite understand why in SPARQL they haven\'t implemented the basic logic operators. However in most of the cases is possible to obtain the same result in a number of wa

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  •  感情败类
    2021-02-02 09:53

    I'm not entirely sure why you say SPARQL doesn't supply 'the basic logic operators', because your own examples clearly show that it does: it provides logical-OR (||) and logical-AND (&&) as part of FILTER conditions, and disjunctive graph patterns using UNION (of course, conjunctive graph patterns need no special syntax).

    Other variations of OR-like constructs are also possible. For queries of the form "this particular value must be one of these possibilities" you can use the set membership operator, IN:

    SELECT * 
    WHERE { 
        ?s ?p ?o.
        FILTER (?p IN (:propA, :propB, :propC ) )
    }
    

    You can also use the VALUES clause for this kind of pattern:

    SELECT * 
    WHERE {
        VALUES ?p { :propA :propB :propC } 
        ?s ?p ?o.
    }
    

    Update I forgot one, perhaps the simplest. For queries such as yours, where you are looking for a few alternatives for a property name, you can actually use a property path expression as well, like so:

    SELECT * 
    WHERE {
        ?s :propA|:propB|:propC ?o.
    }
    

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