Abstract
SPARQL is a standard query language for RDF data that are commonly used to represent and store Semantic Web data. There are a lot of SPARQL endpoints to retrieve and see the data by SPARQL queries. Although it greatly helps us query semantic data with ontologies, their diversity of ontologies make it difficult to query the data without understanding of their target ontologies. Although it is possible to use ontology mapping techniques to convert a query based on an ontology to another one based on another ontology, it is assumed to be able to define complete mappings among the two ontologies without any loss of their semantics. In this paper, we present an approach about SPARQL query rewriting when ontology mappings are not complete. We show a way of rewriting a SPARQL query with one ontology to another query on a different ontology when we can specify an ordering based on their mapping reliability.