Why does this query (on BaseX 7.5, basexgui)
let $ns := namespace {''} {'the-namespace'} let $c1 := <c xmlns="the-namespace">text</c> let $c2 := <c>{ $ns,'text'}</c> let $c3 := element {'c'} {$ns,'text'} let $qn := QName($ns, 'c') let $c4 := element {$qn} {'text'} let $nl := " " return ($c1,$nl, $c2,$nl, $c3,$nl, $c4,$nl, '|' || namespace-uri-from-QName(node-name($c1)) || '|',$nl, '|' || namespace-uri-from-QName(node-name($c2)) || '|',$nl, '|' || namespace-uri-from-QName(node-name($c3)) || '|',$nl, '|' || namespace-uri-from-QName(node-name($c4)) || '|',$nl)
outputs
<c xmlns="the-namespace">text</c> <c xmlns="the-namespace">text</c> <c xmlns="the-namespace">text</c> <c xmlns="the-namespace">text</c> |the-namespace| || || |the-namespace|
I.e, the namespace seems to exist on all four cases when outputted, by node-name finds it only if the namespace is given in element as text, or as QName value in computed element.
-- Arto Viitanen Microteam Oy Finland