xQuery - count function

xquery

Solution

Similar to @koopajah's answer and since I already wrote it I'll submit it...

for $category in distinct-values(/*/book/@category)
where count(/*/book[@category=$category]) >= 3
return
    <results>{$category}</results>

With an external doc...

let $doc := doc('input.xml')

for $category in distinct-values($doc/*/book/@category)
where count($doc/*/book[@category=$category]) >= 3
return
    <results>{$category}</results>

Modified xquery from comment...

for $x in doc('input.xml')/bookstore 
for $y in distinct-values($x/book/@category) 
where count($x/book[@category=$y]) >= 3 
return $y

Problem

Im looking to form an xQuery which returns the category of a book if this category contains more than x amount of books. For example if I have 4 categories; music, film, education, health and they all have 1 book in, apart from music which has 3, im looking to list that category. Ive tried a range of queries but cant seem to get it right, I just get no result everytime, I believe I need to be using distinct-value at some point? Not too sure. An example of the source can be seen below, im testing the query in an editor which doesnt save the source as a file so for me to test the xQuery has to start with: e.g. for $x in /bookstore/book... ``` <bookstore> <book category="Music"> <year>  2005  </year> <price>  50  </price> </book> <book category="Music"> <year>  2010  </year> <price>  35  </price> </book> <book category="Music"> <year>  1982  </year> <price>  70  </price> </book> <book category="Film"> <year>  2000  </year> <price>  10  </price> </book> <book category="Health"> <year>  1965  </year> <price>  50  </price> </book> <book category="Education"> <year>  2012  </year> <price>  70  </price> </book> </bookstore> ``` Any help is massively appreciated!

Original source