Oracle 21c

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--remove one node
SELECT XMLQUERY(
         'copy $NEWHTML := .
         modify (
           for $i in $NEWHTML/ROWSET/ROW/field_without_interest
           for $j in $NEWHTML/ROWSET/ROW/PERSON_NUMBER

           return delete node $i
         )
         return $NEWHTML'
         PASSING xmltype(
  '<?xml version="1.0"?> 
  <ROWSET> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
      <field_without_interest>f</field_without_interest>
    </ROW> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
    </ROW> 
  </ROWSET>'
)
         RETURNING CONTENT
       ).getStringVal() AS interested_elements
FROM   DUAL


INTERESTED_ELEMENTS


<?xml version="1.0"?><ROWSET><ROW><PERSON_NUMBER>1000142</PERSON_NUMBER><LOAN_1>25000</LOAN_1></ROW><ROW><PERSON_NUMBER>1000142</PERSON_NUMBER><LOAN_1>25000</LOAN_1></ROW></ROWSET>


SELECT XMLQUERY(
         'copy $NEWHTML := .
         modify (
           for $i in $NEWHTML/ROWSET/ROW/field_without_interest
           for $j in $NEWHTML/ROWSET/ROW/PERSON_NUMBER
           return delete node $i, node $j
         )
         return $NEWHTML'
         PASSING xmltype(
  '<?xml version="1.0"?> 
  <ROWSET> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
      <field_without_interest>f</field_without_interest>
    </ROW> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
    </ROW> 
  </ROWSET>'
)
         RETURNING CONTENT
       ).getStringVal() AS interested_elements
FROM   DUAL
ORA-19114: XPST0003 - error during parsing the XQuery expression: 
LPX-00801: XQuery syntax error at 'j'
5              return delete node $i, node $j
-                                           ^

SELECT XMLQUERY(
         'copy $NEWHTML := .
         modify (
           for $i in $NEWHTML/ROWSET/ROW/field_without_interest
           for $j in $NEWHTML/ROWSET/ROW/PERSON_NUMBER
           return delete node $i, 
           return delete node $j
         )
         return $NEWHTML'
         PASSING xmltype(
  '<?xml version="1.0"?> 
  <ROWSET> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
      <field_without_interest>f</field_without_interest>
    </ROW> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
    </ROW> 
  </ROWSET>'
)
         RETURNING CONTENT
       ).getStringVal() AS interested_elements
FROM   DUAL
ORA-19114: XPST0003 - error during parsing the XQuery expression: 
LPX-00801: XQuery syntax error at 'delete'
6              return delete node $j
-                     ^

SELECT XMLQUERY(
         'copy $NEWHTML := .
         modify (
            for $j in $NEWHTML/ROWSET/ROW/PERSON_NUMBER
            return delete node $j
         )
         modify (
           for $i in $NEWHTML/ROWSET/ROW/field_without_interest
           return delete node $i, 
           
         )
         return $NEWHTML'
         PASSING xmltype(
  '<?xml version="1.0"?> 
  <ROWSET> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
      <field_without_interest>f</field_without_interest>
    </ROW> 
    <ROW>
      <PERSON_NUMBER>1000142</PERSON_NUMBER>
      <LOAN_1>25000</LOAN_1>
    </ROW> 
  </ROWSET>'
)
         RETURNING CONTENT
       ).getStringVal() AS interested_elements
FROM   DUAL
ORA-19114: XPST0003 - error during parsing the XQuery expression: 
LPX-00801: XQuery syntax error at 'modify'
6            modify (
-            ^