DevOps, CI/CD and Automation

I can't figure out how to put PL/SQL function inside XMLQuery update statement.

i.e

SELECT

XMLQuery('copy $i := $p1 modify

                    ( for $j in $i//Company return replace value of node $j with "my PL/SQL function (this node)" )

                  return $i'

                  PASSING

                              MyData AS "p1"

                    RETURNING CONTENT)

from MyTable;

BTW, I tried '||' , it doesn't work.