Query with WHERE

• List titles of books published by Addison-Wesley

  <bib>
     FOR $b IN document("http://www.bn.com")/bib/book
     WHERE $b/publisher = "Addison-Wesley"
     RETURN
       $b/title
  </bib>
  

• This WHERE clause could be replaced by an XPath predicate:

  <bib>
     FOR $b IN document("http://www.bn.com")/bib/book[publisher="Addison-Wesley"]
     RETURN
       $b/title
  </bib>
  

• But WHERE clauses can combine multiple variables from multiple documents

Adapted from XML Query Use Cases