XQuery FLWR Expression Example

List the titles of books published by Morgan Kaufmann in 1998.

	for $b in document("bib.xml")//book
	where $b/publisher = "Morgan Kaufmann"
	  and $b/year = "1998"
	return { $b/title }
   

List each publisher and the average price of its books.

	for $p in distinct(document("bib.xml")//publisher)
	  let $a := avg(document("bib.xml")/book[publisher = $p]/price)
	return
	  <publisher> 
		<name> { $p/text() } </name> 
		<avgprice> { $a } </avgprice> 
	  </publisher>