XQuery FLWOR Expressions
The XML Example Document
We will use the "books.xml" document in the examples below (same
XML file as in the previous chapter).
View the "books.xml" file in your browser.
How to Select Nodes From "books.xml" With FLWOR
Look at the following path expression:
| doc("books.xml")/bookstore/book[price>30]/title |
The expression above will select all the title elements under the book
elements that are under the bookstore element that have a price element with a
value that is higher than 30.
The following FLWOR expression will select exactly the same as the path expression above:
for $x in doc("books.xml")/bookstore/book
where $x/price>30
return $x/title |
The result will be:
<title lang="en">XQuery Kick Start</title>
<title lang="en">Learning XML</title> |
With FLWOR you can sort the result:
for $x in doc("books.xml")/bookstore/book
where $x/price>30
order by $x/title
return $x/title |
FLWOR is an acronym for "For, Let, Where, Order by, Return".
The for clause selects all book elements under the bookstore
element into a variable called $x.
The where clause selects only book elements with a price
element with a value greater than 30.
The order by clause defines the sort-order. Will be sort by
the title element.
The return clause specifies what should be returned. Here it returns the title
elements.
The result of the XQuery expression above will be:
<title lang="en">Learning XML</title>
<title lang="en">XQuery Kick Start</title>
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