Query Issues (SPARQL, SQL, etc.) bif:contains and REGEX Searches Produce Different Results bif:contains looks for phrases or independent words, and it may normalize words that use non-canonical Unicode chars. It can also search in XML/HTML documents. In addition, even if one and the same query string is valid for both REGEX and bif:contains, then the meaning may differ. For REGEX, pattern "Paris Hilton" is precisely two words delimited by single whitespace byte. For bif:contains, "Paris Hilton" means that the document should contain word "Paris" and word "Hilton", in any places and in any order. See http://docs.openlinksw.com/virtuoso/queryingftcols.html for details of bif:contains query string syntax.