Oracle 18c

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select extractvalue(
  xmltype('<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" 
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<getAddressForIpResponse xmlns="urn:USR1">
<p-address xsi:type="xsd:string">11.11.11.11:2222</p-address>
</getAddressForIpResponse>
</soap:Body>
</soap:Envelope>'), 
  '/soap:Envelope/soap:Body/getAddressForIpResponse/p-address',
  'xmlns="urn:USR1" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"')
from dual;


EXTRACTVALUE(XMLTYPE('<?XMLVERSION="1.0"ENCODING="UTF-8"?><SOAP:ENVELOPEXMLNS:XSI="HTTP://WWW.W3.ORG/2001/XMLSCHEMA-INSTANCE"XMLNS:SOAPENC="HTTP://SCHEMAS.XMLSOAP.ORG/SOAP/ENCODING/"XMLNS:XSD="HTTP://WWW.W3.ORG/2001/XMLSCHEMA"SOAP:ENCODINGSTYLE="HTTP:


11.11.11.11:2222


select XMLQuery(
  'declare default element namespace "urn:USR1";
   declare namespace soap="http://schemas.xmlsoap.org/soap/envelope/";
   /soap:Envelope/soap:Body/getAddressForIpResponse/p-address/text()'
  passing xmltype('<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" 
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<getAddressForIpResponse xmlns="urn:USR1">
<p-address xsi:type="xsd:string">11.11.11.11:2222</p-address>
</getAddressForIpResponse>
</soap:Body>
</soap:Envelope>')
  returning content).getStringval()
from dual;


XMLQUERY('DECLAREDEFAULTELEMENTNAMESPACE"URN:USR1";DECLARENAMESPACESOAP="HTTP://SCHEMAS.XMLSOAP.ORG/SOAP/ENVELOPE/";/SOAP:ENVELOPE/SOAP:BODY/GETADDRESSFORIPRESPONSE/P-ADDRESS/TEXT()'PASSINGXMLTYPE('<?XMLVERSION="1.0"ENCODING="UTF-8"?><SOAP:ENVELOPEXML


11.11.11.11:2222


select ip_address
from XMLTable (
  XMLNamespaces (
    default 'urn:USR1',
    'http://schemas.xmlsoap.org/soap/envelope/' as "soap"
  ),
  '/soap:Envelope/soap:Body/getAddressForIpResponse/p-address'
  passing xmltype('<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" 
xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" 
xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<getAddressForIpResponse xmlns="urn:USR1">
<p-address xsi:type="xsd:string">11.11.11.11:2222</p-address>
</getAddressForIpResponse>
</soap:Body>
</soap:Envelope>')
  columns ip_address varchar2(15) path '.');


IP_ADDRESS


11.11.11.11:222