XML Oracle：从多个重复的子节点中提取特定属性

Question

I'm having trouble understanding other questions I see, as they are a little bit different.

I'm getting a XML as response from a webservice vi UTL_HTTP. The XML has repeating child nodes and I want to extract only 1 specific value.

The response XML:

<Customer>
    <Loyalty>
       <Client>
          <Identifications>
              <Identification>
                   <Form>Form1</Form>
                   <value>1234</value>
              </Identification>
              <Identification>
                   <Form>Form2</Form>
                   <value>4442</value>
              </Identification>
              <Identification>
                   <Form>Form3</Form>
                   <value>9995</value>
              </Identification>
           </Identifications>
       </Client>
    </Loyalty>
 </Customer>

I need to extract the the node <value> only where the node <Form> = "Form3".

So, within my code, I receive the response from another function

v_ds_xml_response XMLTYPE;
-- Here would lie the rest of the code (omitted) preparing the XML and next calling the function with    it:

V_DS_XML_RESPONSE := FUNCTION_CALL_WEBSERVICE(
      P_URL => V_DS_URL, --endpoint
      P_DS_XML => V_DS_XML, --the request XML
      P_ERROR => P_ERROR); 

With that, I created a LOOP to store the values. I've tried using WHERE and even creating a type (V_IDENTIFICATION below is the type), but It didn't return anything (null).

for r IN (
SELECT         
 ExtractValue(Value(p),'/Customer/Loyalty/Client/Identifications/Identification/*[local-name()="Form"]/text()') as form, 
     ExtractValue(Value(p),'/Customer/Loyalty/Client/Identifications/Identification/*[local-name()="value"]/text()') as value
   FROM   TABLE(XMLSequence(Extract(V_DS_XML_RESPONSE,'//*[local-name()="Customer"]'))) p

LOOP
V_IDENTIFICATION.FORM   := r.form;
V_IDENTIFICATION.VALUE  := r.value;
END LOOP;

SELECT 
       V_IDENTIFICATION.VALUE
INTO   
       P_LOYALTY_VALUE
FROM   dual
WHERE  V_IDENTIFICATION.TIPO = 'Form3';

Note, P_LOYALTY_VALUE is an OUT parameter from my Procedure

Answer 1

with this sql you should get the desired value:

with data as
 (select '<Customer>
   <Loyalty>
   <Client>
      <Identifications>
          <Identification>
               <Form>Form1</Form>
               <value>1234</value>
          </Identification>
          <Identification>
               <Form>Form2</Form>
               <value>4442</value>
          </Identification>
          <Identification>
               <Form>Form3</Form>
               <value>9995</value>
          </Identification>
       </Identifications>
   </Client>
</Loyalty>
</Customer>' as xmlval
    from dual b)
 (SELECT t.val
    FROM data d,
         xmltable('/Customer/Loyalty/Client/Identifications/Identification'
                  PASSING xmltype(d.xmlval) COLUMNS 
                  form VARCHAR2(254) PATH './Form',
                  val VARCHAR2(254) PATH './value') t
   where t.form = 'Form3');

Answer 2

When you don't know exact path.

select * from 
xmltable('for $i in $doc//*/Form
 where $i = "Form2"
 return $i/../value'
passing 
xmltype('<Customer>
    <Loyalty>
       <Client>
          <Identifications>
              <Identification>
                   <Form>Form1</Form>
                   <value>1234</value>
              </Identification>
              <Identification>
                   <Form>Form2</Form>
                   <value>4442</value>
              </Identification>
              <Identification>
                   <Form>Form3</Form>
                   <value>9995</value>
              </Identification>
           </Identifications>
       </Client>
    </Loyalty>
 </Customer>') as "doc" ) 

Answer 3

To extract the value you're looking for you can use the following XPATH expression:

/Customer/Loyalty/Client/Identifications/Identification/Form[text()='Form3']/../value

Test it here

Then you can use XMLTABLE function to get the result

SELECT my_value
FROM xmltable(
        '/Customer/Loyalty/Client/Identifications/Identification/Form[text()=''Form3'']/../value'
        PASSING xmltype(
'<Customer>
    <Loyalty>
        <Client>
        <Identifications>
            <Identification>
                <Form>Form1</Form>
                <value>1234</value>
            </Identification>
            <Identification>
                <Form>Form2</Form>
                <value>4442</value>
            </Identification>
            <Identification>
                <Form>Form3</Form>
                <value>9995</value>
            </Identification>
        </Identifications>
        </Client>
    </Loyalty>
</Customer>')
        COLUMNS
            my_value VARCHAR2(4000) path '/value'
    )

Answer 4

Aaand I managed to find the solution, which is quite simple, just added [text()="Form3"]/.../" to predicate the Xpath as in

SELECT         
ExtractValue(Value(p),'/Customer/Loyalty/Client/Identifications/Identification/*[local-name()="Form"][text()="Form3"]/text()') as form, 
 ExtractValue(Value(p),'/Customer/Loyalty/Client/Identifications/Identification/Form[text()="Form3"]/.../*[local-name()="value"]/text()') as value

Also extracted the values just sending them directly into the procedure's OUT parameter:

P_FORM := r.form;
P_LOYALTY_VALUE := r.value;