Is it build on top of XPath and works like SQL for databases.
It is even suported by databases as querying language - see Posgres and XMLTable
for $x in doc("books.xml")/bookstore/book
where $x/price>30
order by $x/title
return $x/title
Looks like this
<ul>
{
for $x in doc("books.xml")/bookstore/book/title
order by $x
return <li>{$x}</li>
}
</ul>
You can even query to HTML
let $sum := sum(doc("books.xml")/bookstore/book/price)
return <ul>
{
for $x in doc("books.xml")/bookstore/book/title
order by $x
return <li>{$x}</li>
}
<li>Order x, total sum {$sum}</li>
</ul>
Or add variables
let $items := (1,2,3,4,5,"Different type", <div>Even HTML element</div>)
let $count := count($items)
return
<result>
<count>{$count}</count>
<items>
{
for $item in $items[2]
return <item>{$item}</item>
}
</items>
</result>
Sequences
declare function local:write-paragraph($article) {
for $text in $article/text return <p>{$text/node()}</p>
};
$article = doc("article.xml")/articles/article
local:write-paragraph($article)
Templates
Let's try it :)
Btw nice tutorial is here: https://www.tutorialspoint.com/xquery/index.htm
