xquery distinct-values and group by and selecting xquery 1.0 - xquery

Question

I have a structure then have elements with same value, but any elements change the value.
I need group the information and mount the output.
<root>
<cadastro>
<id>2</id>
<nome>abcd</nome>
<links>
<link>example7</link>
</links>
</cadastro>
<cadastro>
<id>2</id>
<nome>abc</nome>
<links>
<link>example5</link>
<link>example3</link>
</links>
</cadastro>
<cadastro>
<id>5</id>
<nome>xpto</nome>
<links>
<link>example1</link>
</links>
</cadastro>
</root>
I must to return only 2 outputs
<results>
<result>
<idResult>2</idResult>
<nome>abc</nome>
<links>
<url>example7</url>
<url>example5</url>
<url>example3</url>
</links>
</result>
<result>
<idResult>5</idResult>
<nome>xpto</nome>
<links>
<url>example1</url>
</links>
</result>
<results>
I tried to use the distinct-values but i have differents values to same id at payload.
How i can to group by at xquery 1.0?

Answer 1

You can use distinct-values to iterate over unique IDs, and query for every matching element with that ID.
However, note one difference in this output: the <nome> values for elements matching 2 are different, and your example only returns one of them. But it's not clear which one is the correct one, so this solution outputs both. If you want only one match, then you need to add a constraint, which could be as simple as ($id-results/nome)[1], but there's no guarantee that will select the one you want.
element results {
let $ids := $data/cadastro/id
for $id in distinct-values($ids)
let $id-results := $data/cadastro[id = $id]
return element result {
element idResult { $id },
$id-results/nome,
element links {
$id-results/links/link
}
}
=>
<results>
<result>
<idResult>2</idResult>
<nome>abcd</nome>
<nome>abc</nome>
<links>
<link>example7</link>
<link>example5</link>
<link>example3</link>
</links>
</result>
<result>
<idResult>5</idResult>
<nome>xpto</nome>
<links>
<link>example1</link>
</links>
</result>
</results>