Minor Description
When using a blank node in the graph pattern of a query, using "select distinct *" can result in duplicate rows. There is a similar issue with "select reduced *"
Steps to reproduce:
1) Load the "books" database [1]
2) Add an additional statement [2]
3) Run the following query:
PREFIX books: <http://example.org/book/>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
select distinct *
where
You see that you get a duplicate result for book5.
If you change the query to:
PREFIX books: <http://example.org/book/>
PREFIX dc: <http://purl.org/dc/elements/1.1/>
select distinct ?book ?title
where
You do not get duplicates.
[1] http://svn.apache.org/repos/asf/incubator/jena/Jena2/Fuseki/trunk/Data/books.ttl
[2] <http://example.org/book/book5> <http://purl.org/dc/elements/1.1/creator> "Sir Example" .