I need to aggregate some sub-tag values into a Oracle SQL column.

Let’s say the XML structure is something like this:

<Product>
[..other tags..]
 <Attributes>
   <Statements Id="1" Name="Statement 0">
     <Statement Id="4">Subtype 1</Statement>
   </Statements>
   <Statements Id="3" Name="Statement 1">
     <Statement Id="4">Subtype 4</Statement>
     <Statement Id="5">Subtype 5</Statement>
     <Statement Id="15">Subtype 15</Statement>
   </Statements>
   <Statements Id="16" Name="Statement 2">
     <Statement Id="4">Subtype 4</Statement>
     <Statement Id="5">Subtype 5</Statement>
     <Statement Id="10">Subtype 10</Statement>
   </Statements>
 </Attributes>
</Product>

My Product table in SQL should be populated with something like this:
Statement_2 with entry Subtype4,Subtype5,Subtype10…
etc..

I actually tryed to use some query like the following:

SELECT 
    b.id,
    LISTAGG(x2.statement_1, ',') WITHIN GROUP (ORDER BY NULL) AS statement 1,
    LISTAGG(y2.statement_2, ',') WITHIN GROUP (ORDER BY NULL) AS statement_2
FROM 
    TABLE_WHERE_XML_RESIDES b

CROSS JOIN 
    XMLTABLE('/root_path/Statements[@Id="3"]' 
             PASSING XMLTYPE(b.XML_DOCUMENT)
             COLUMNS statement1_list XMLTYPE PATH 'Statement') x
CROSS JOIN 
    XMLTABLE('/Statement' 
             PASSING x.statement1_list 
             COLUMNS statement_name_1 VARCHAR2(100) PATH 'text()') x2

CROSS JOIN 
   XMLTABLE('/root_path/Statements[@Id="16"]' 
             PASSING XMLTYPE(b.XML_DOCUMENT)
             COLUMNS statement1_list XMLTYPE PATH 'Statement') y

CROSS JOIN 
    XMLTABLE('/Statement' 
             PASSING x.statement2_list 
             COLUMNS statement_name_1 VARCHAR2(4000) PATH 'text()') y2
GROUP BY 
    b.id;

In this way the aggregation kinda of works, but for many the query will be not performant I guess. And main problem is, due to the join mechanisms subsequent statements values (i.e. statements 2) would be duplicated for N times (which correspond to the N entries already retreived for the column in statement1.

Sorry it’s really hard to explain this.. I’m open to discuss any suggestion / consideration!
Thanks.