Using the XML Document below (library with books), define the following queries in XQuery: (a) Give the titles of all Books sorted by Price. (b) How many books were written by Abiteboul? (c) Give for each author, the number of books he has written.

Explanation:

a)use order by clause for sorting

for $x in doc("books.xml")/bib/book order by xs:float($x/price) return $x/title (default sorted in ascending order)

or

for $x in doc("books.xml")/bib/book order by xs:float($b/price) descending  return $b/title (sorted in descending order)

b)doc("books.xml")//book[author = 'Abiteboul']

c)for $x in distinct-values(doc("bib.xml")/bib/book/author)

return <res>

<name>{$x}</name>

<count>

 {count (doc("bib.xml")//book[exists(indexof(author,$x))]) }

</count>

<res>