eXist, XQuery & flowr - order results by element and limit number returned by position

Hi,

I would like to present a summary of reports in an eXist database, ordered by a user-defined element, and then return only a subset of these reports (allow paging of results).

The number of reports that are queried exceeds 1500, and I would like to limit the XML transferred to the client. The following XQuery facilitates paging of results, however the $pos variable refers to the original position of the record in the collection and not the position of the record after it has been ordered by the selected element.

Is it is possible to retrieve the position of a record in a recordset, after it has been ordered, or is it necessary to select all records and then use the XSLT processor to retrieve records with the required position() value?

thank you for any info

Tanya


*********************************************************************************************

<xdb:query collection="/db/{$db-name}/reports" create-collection="true"
xmlns:xmldb="http://exist-db.org/xquery/xmldb"
xmlns:util="http://exist-db.org/xquery/util"
>

xquery version "1.0";
declare namespace fn='http://www.w3.org/2005/02/xpath-functions';
declare namespace xmldb='http://exist-db.org/xquery/xmldb';
<result >
{
 
for $x at $pos in /*
   <xsl:value-of select='$order-by'/>

    return
   
    if (($pos gt <xsl:value-of select='$from'/>)
        and ($pos lt <xsl:value-of select='$to'/>))  then
 
<report>  
   
<xsl:for-each select="doc('input:config-options')//report-summary/elements/element">
   
   { $x//*[name() = '<xsl:value-of select = "."/>']}
   
    </xsl:for-each>
   
<author>{doc('/db/<xsl:value-of select='$db-name'/>/user-accounts/Users.xml')//user[user-activity/report/@document-id= util:document-name($x)]/user-record/username/text()}</author>
<filename label='Filename'>{util:document-name($x)}</filename>
<date-modified>{xmldb:last-modified('/db/<xsl:value-of select='$db-name'/>/reports', util:document-name($x))}</date-modified>
    <position>{$pos}</position>    
       
</report>
   
    else
<null/>
 
}
</result>
</xdb:query>

****************************************************************************************





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