如何计算同名元素？ XML-> Xquery

Question

i have a xml doc like:

<root>
<test>
    <humans>
        <names>Tim</names>
    </humans>
</test>
<test>
    <humans>
        <names>Jack</names>
        <names>Jones</names>
    </humans>
</test>
<test>
    <humans>
        <names>Tim</names>
    </humans>
</test>
</root>

and I want to count all names which are the same: Tim 2, Jack 1, Jones 1 and it should give an output like:

<x> Tim </x> 

because TIM is the highest name

I hope you can help me... (sorry for my bad english)

Answer 1

In XPath 2.0, XSLT 2.0 and XQuery use (exactly the same solution):

(/*/*/*/names[for $v in .,
                    $cnt in count(/*/*/*/names[. eq $v])
                 return
                    $cnt
                   eq
                     max(for $n in distinct-values(/*/*/*/names)
                           return
                              count(/*/*/*/names[. eq $n])
                        )
                ]
    )[1]

You can also get this element easily with the following XSLT 1.0 transformation :

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:key name="kNamesByVal" match="names" use="."/>

 <xsl:template match="/">
  <xsl:for-each select=
   "*/*/*/names[generate-id()
               =
                generate-id(key('kNamesByVal',.)[1])
               ]">
   <xsl:sort select="count(key('kNamesByVal',.))"
    data-type="number" order="descending"/>

    <xsl:if test="position()=1">
      <xsl:copy-of select="."/>
    </xsl:if>
  </xsl:for-each>
 </xsl:template>
</xsl:stylesheet>

When the above XPath 2.0/XQuery expression or XSLT transformation are evaluated (applied) on the provided XML document :

<root>
    <test>
        <humans>
            <names>Tim</names>
        </humans>
    </test>
    <test>
        <humans>
            <names>Jack</names>
            <names>Jones</names>
        </humans>
    </test>
    <test>
        <humans>
            <names>Tim</names>
        </humans>
    </test>
</root>

the correct element is selected (produced):

<names>Tim</names>

Answer 2

let $xml := <!-- your xml document -->
return
(
  for $name in distinct-values($xml//names)
  order by count($xml//names[. = $name]) descending
  return <x>{$name}</x>
)[1]

Answer 3

The solution of Gunther is the best, and if you wanted to count every elements you could do:

xquery version "1.0";

for $x in
(
  for $name in distinct-values(//names)
  order by count(//names[. = $name]) descending
  return <x>{$name}</x>
) return fn:concat($x, ' - ',xs:string(count(//names[. = $x])))

With result Tim - 2 Jack - 1 Johons - 1