Here's one thing you may be asking - do you want to know how to specify a join for n sources? If so, maybe this example will help:
declare variable $eng := (<d n="1">one</d>, <d n="2">two</d>, <d n="3">three</d>, <d n="4">four</d>); declare variable $deu := (<d n="1">eins</d>, <d n="2">zwei</d>, <d n="3">drei</d>, <d n="4">vier</d>); declare variable $ukr := (<d n="1">один</d>, <d n="2">два</d>, <d n="3">три</d>, <d n="4">чотири</d>); declare variable $heb := (<d n="1">אחד</d>, <d n="2">שתיים</d>, <d n="3">שלוש</d>, <d n="4">ארבע</d>);
for $e in $eng for $d in $deu for $u in $ukr for $h in $heb where $e/@n = $d/@n and $e/@n = $u/@n and $e/@n = $h/@n return <wf>{ $e, $d, $u, $h }</wf>
This returns:
<wf> <d n="1">one</d> <d n="1">eins</d> <d n="1">один</d> <d n="1">אחד</d> </wf> <wf> <d n="2">two</d> <d n="2">zwei</d> <d n="2">два</d> <d n="2">שתיים</d> </wf> <wf> <d n="3">three</d> <d n="3">drei</d> <d n="3">три</d> <d n="3">שלוש</d> </wf> <wf> <d n="4">four</d> <d n="4">vier</d> <d n="4">чотири</d> <d n="4">ארבע</d> </wf>
Does that answer your question? I routinely do queries that join multiple sources.
Jonathan On Tue, Apr 19, 2022 at 6:04 AM Markus Elfring Markus.Elfring@web.de wrote:
Have you read the XQuery specifications?
Yes.
This section on joins, written by one of the inventors of SQL, may be a
helpful starting point:
It seems that I stumble on communication difficulties for this application area.
Regards, Markus