Is it possible to simplify this SPARQL query?

Question

I am currently implementing SPARQL queries for LDBC Benchmark . I came up with a bi-read-3 solution. Relevant part of the data schema:

Request Description:

Find the tags that were used in the messages for the specified month of the given year, and the tags that were used during the next month. For both months, calculate the number of posts that each tag used.

My solution ( with syntax highlighting ):

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX sn: <http://www.ldbc.eu/ldbc_socialnet/1.0/data/> PREFIX snvoc: <http://www.ldbc.eu/ldbc_socialnet/1.0/vocabulary/> PREFIX sntag: <http://www.ldbc.eu/ldbc_socialnet/1.0/tag/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX dbpedia: <http://dbpedia.org/resource/> PREFIX dbpedia-owl: <http://dbpedia.org/ontology/> SELECT ?tagName (SUM(?countMonth1) as ?countMonth1) (SUM(?countMonth2) as ?countMonth2) (ABS( SUM(?countMonth1) - SUM(?countMonth2) ) as ?diff) WHERE { { SELECT ?tagName (COUNT(?message) as ?innerCountMonth1) WHERE { BIND ( 2010 as ?year1 ) . BIND ( 9 as ?month1 ) . { ?message rdf:type snvoc:Comment } UNION { ?message rdf:type snvoc:Post } . ?message snvoc:creationDate ?creationDate . FILTER ((year(?creationDate) = ?year1 && month(?creationDate) = ?month1) ) ?message snvoc:hasTag ?tag . ?tag foaf:name ?tagName . } GROUP BY ?tagName } UNION { SELECT ?tagName (COUNT(?message) as ?innerCountMonth2) WHERE { BIND ( 2010 as ?year1 ) . BIND ( 9 as ?month1 ) . BIND ( ?year1 + FLOOR(?month1 / 12.0) as ?year2 ) . BIND ( IF (?month1 = 12, 1, ?month1 + 1) as ?month2 ) . { ?message rdf:type snvoc:Comment } UNION { ?message rdf:type snvoc:Post } . ?message snvoc:creationDate ?creationDate . FILTER (year(?creationDate) = ?year2 && month(?creationDate) = ?month2 ) ?message snvoc:hasTag ?tag . ?tag foaf:name ?tagName . } GROUP BY ?tagName } BIND ( COALESCE(?innerCountMonth1, 0) as ?countMonth1 ) BIND ( COALESCE(?innerCountMonth2, 0) as ?countMonth2 ) } GROUP BY ?tagName ORDER BY DESC(?diff) ?tagName 

I have a feeling that there is a simpler solution, but I can’t figure it out.

My question is: can this request be implemented in a simpler and more efficient way? For example: without nested queries or just a faster way.

I'm really new to SPARQL, so I would appreciate every helpful comment or improvement.

Answer 1

 PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX snvoc: <http://www.ldbc.eu/ldbc_socialnet/1.0/vocabulary/> PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?tagName (SUM(xsd:integer(?isFirst)) AS ?countMonth1) (SUM(xsd:integer(?isSecond)) AS ?countMonth2) (ABS(?countMonth1 - ?countMonth2) AS ?diff) WHERE { VALUES (?year1 ?month1) {(2010 9)} VALUES (?type) {(snvoc:Comment) (snvoc:Post)} ?message a ?type; snvoc:hasTag/foaf:name ?tagName; snvoc:creationDate ?creationDate . BIND (year(?creationDate) AS ?year) . BIND (month(?creationDate) AS ?month) . BIND (IF (?month1 = 12, ?year1 + 1, ?year1 ) AS ?year2) . BIND (IF (?month1 = 12, 1, ?month1 + 1) AS ?month2) . BIND (((?month1 = ?month) && (?year1 = ?year)) AS ?isFirst) . BIND (((?month2 = ?month) && (?year2 = ?year)) AS ?isSecond) . FILTER (?isFirst || ?isSecond) } GROUP BY ?tagName HAVING (bound(?tagName)) 

Update

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