Changes

'''Example:'''

for $country in db:open('factbook')//country

where $country/@population > 100000000

count $id

return <country id='{ $id }' name='{ $name }'>{ $city/name }</country>

==group by==

'''XQuery:'''

for $ppl in doc('xmark')//people/person

let $ic := $ppl/profile/@income

order by $income

return element { $income } { count($ppl) }

This query is a rewrite of [http://www.ins.cwi.nl/projects/xmark/Assets/xmlquery.txt Query #20] contained in the [http://www.ins.cwi.nl/projects/xmark XMark Benchmark Suite] to use <code>group by</code>.

'''Result:'''

<challenge>4731</challenge>

<na>12677</na>

<preferred>314</preferred>

<standard>7778</standard>

In contrast to the relational GROUP BY statement, the XQuery counterpart concatenates the values of all non-grouping variables that belong to a specific group. In the context of our example, all nodes in <code>//people/person</code> that belong to the <code>preferred</code> partition are concatenated in <code class="brush:xquery">$ppl</code> after grouping has finished. You can see this effect by changing the return statement to:

...

return element { $income } { $ppl }

'''Result:'''

<challenge>

<person id="person0">

…

</challenge>

Moreover, a value can be assigned to the grouping variable. This is shown in the following example:

'''XQuery:'''

let $data :=

<xml>

$person/@name ! element name { data() }

}

'''Result:'''

<persons country="USA">

<name>John</name>

<name>Johann</name>

</persons>

==count==

The {{Code|count}} clause enhances the FLWOR expression with a variable that enumerates the iterated tuples.

for $n in (1 to 10)[. mod 2 = 1]

count $c

return &lt;number count="{ $c }" number="{ $n }"/&gt;

==allowing empty==

The {{Code|allowing empty}} provides functionality similar to outer joins in SQL:

for $n allowing empty in ()

return 'empty? ' || empty($n)

==window==

Window clauses provide a rich set of variable declarations to process sub-sequences of iterated tuples. An example:

for tumbling window $w in (2, 4, 6, 8, 10, 12, 14)

start at $s when fn:true()

only end at $e when $e - $s eq 2

return &lt;window&gt;{ $w }&lt;/window&gt;

More information on window clauses, and all other enhancements, can be found in the [http://www.w3.org/TR/xquery-30/#id-windows specification].

<ul>

<li>Declaring a new ''inline function'':

'''Result:''' <code>42</code>

</li>

<li>Getting the function item of an existing (built-in or user-defined) XQuery function. The arity (number of arguments) has to be specified as there can be more than one function with the same name:

'''Result:''' <code>25</code>

</li>

<li>''Partially applying'' another function or function item. This is done by supplying only some of the required arguments, writing the placeholder <code>?</code> in the positions of the arguments left out. The produced function item has one argument for every placeholder.

return (

$f('foo123'),

$f('bar456')

'''Result:''' <code>foo bar</code>

</li>

'''Example:'''

(: Simple map notation :)

(1 to 10) ! element node { . },

for $i in 1 to 10

return element node { $i }

In contrast to path expressions, the results of the map operator will not be made duplicate-free and returned in document order.

'''Example:'''

try {

1 + '2'

'Error [' || $err:code || ']: ' || $err:description

}

'''Result:''' <code>Typing error: '+' operator: number expected, xs:string found.</code>

'''Example:'''

for $fruit in ("Apple", "Pear", "Peach")

return switch ($fruit)

case "Peach" return "pink"

default return "unknown"

'''Result:''' <code>red green pink</code>

'''Example:'''

for $fruit in ("Apple", "Cherry")

return switch ($fruit)

default

return "unknown"

'''Result:''' <code>red red</code>

New namespaces can be created via so-called 'Computed Namespace Constructors'.

element node { namespace pref { 'http://url.org/' } }

=String Concatenations=

Two vertical bars <code>||</code> (also named ''pipe characters'') can be used to concatenate strings. This operator is a shortcut for the {{Code|fn:concat()}} function.

'Hello' || ' ' || 'Universe'

=External Variables=

Default values can be attached to external variable declarations. This way, an expression can also be evaluated if its external variables have not been bound to a new value.

declare variable $user external := "admin";

"User:", $user

=Serialization=

'''Example:'''

declare namespace output = "http://www.w3.org/2010/xslt-xquery-serialization";

declare option output:omit-xml-declaration "no";

declare option output:method "xhtml";

&lt;html/&gt;

'''Result:''' <code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;&lt;html&gt;&lt;/html&gt;</code>

'''Example:'''

declare context item := document {

<xml>

for $t in .//text()

return string-length($t)

'''Result:''' <code>5 5</code>

'''Example:'''

declare %private function local:max($x1, $x2) {

if($x1 > $x2) then $x1 else $x2

local:max(2, 3)

=Functions=