[xquery-talk] Results with distinct-values varies dependent on syntax

[David Carlisle]

On 15/11/2020 12:32, Ihe Onwuka wrote:
> xquery version "3.1";
>
> let $schemaCollection := "/db/apps/schemas"
>  return 
> collection($schemaCollection)/xs:schema/distinct-values(@targetNamespace)
>
> does not eliminate duplicates
>
> xquery version "3.1";
>
> let $schemaCollection := "/db/apps/schemas"
>  return collection($schemaCollection)/xs:schema/@targetNamespace => 
> distinct-values()
>
> does.
>
> I checked this in Saxon and exist-db XQuery, both return the same 
> results so this may be how it's supposed to work but I don't get it.
>
>
>
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distinct-values(@targetNamespace)


returns the input sequence with duplicates (by value) removed but 
@targetNamespace only selects at most one attribute so distinct-values 
will do nothing.

$schemaCollection)/xs:schema/@targetNamespace => distinct-values()

or

distinct-values($schemaCollection)/xs:schema/@targetNamespace)


here you first make the sequence of all the @targetNamespace then remove 
duplicates.


David

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