title: use union in sparql query
body: <p>I've got this SPARQL query between 2 DBpedia resources: France and Alstom</p>
  
  <pre><code>select * where{
  &lt;http://dbpedia.org/resource/France&gt; ?pre ?obj.
  
  ?obj ?pre1 &lt;http://dbpedia.org/resource/Alstom&gt;
  }
  </code></pre>
  
  <p>and it returns nothing </p>
  
  <p>but if I reverse the subject and the object like this:</p>
  
  <pre><code>select * where{
  &lt;http://dbpedia.org/resource/Alstom&gt; ?pre ?obj.
  ?obj ?pre1 &lt;http://dbpedia.org/resource/France&gt;
  }
  </code></pre>
  
  <p>the query returns some results..</p>
  
  <p><a href="http://dbpedia.org/sparql?default-graph-uri=http%3A%2F%2Fdbpedia.org&amp;query=select%20*%20where%7B%0D%0A%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FAlstom%3E%20%3Fpre%20%3Fobj.%0D%0A%3Fobj%20%3Fpre1%20%3Chttp%3A%2F%2Fdbpedia.org%2Fresource%2FFrance%3E%0D%0A%7D%0D%0A&amp;format=text%2Fhtml&amp;timeout=30000&amp;debug=on" rel="nofollow">SPARQL Result</a></p>
  
  <p>is there any way to merge the two queries using UNION?</p>