Oracle query using Xpath to get comma separated List for same node

问题

Hello Everyone, I need a help to fetch comma separated list for same node if exists in XML nodes. My XML is like this which is stored in my database:-

<Event>
    <Detail>
        <List>
            <Element>
                <name>ABC</name>
                <salary>150</salary>
            </Element>
            <Element>
                <name>PQR</name>
                <salary>250</salary>
            </Element>
        </List>
    </Detail>
</Event>

I need to get comma separated name list (ABC,PQR ) from this using xpath oracle query. I have tried alot and when i get a way like this :-

NVL(VALUE (line).EXTRACT ('/Event/Detail/List/Element/name/text()') .getstringval (),'') Name List

Then , my output was ABCPQR.

No Space or comma was there. Could anyone please help me out for this .

Expected output is :- ABC,PQR

Thanks in advance :)

回答1:

You're pulling a list of values out of an XML document, rather than a single value, so I think you'd be better off selecting them all into a table using XMLTABLE and then joining them together with LISTAGG.

Here's an example:

SQL> CREATE TABLE xmltest (id INTEGER, x XMLTYPE);

Table created.

SQL> INSERT INTO xmltest (id, x) VALUES (1, XMLTYPE('<Event>
  2      <Detail>
  3          <List>
  4              <Element>
  5                  <name>ABC</name>
  6                  <salary>150</salary>
  7              </Element>
  8              <Element>
  9                  <name>PQR</name>
 10                  <salary>250</salary>
 11              </Element>
 12          </List>
 13      </Detail>
 14  </Event>'));

1 row created.

SQL> COMMIT;

Commit complete.

SQL> SELECT t.id, LISTAGG(y.name, ',') WITHIN GROUP (ORDER BY ROWNUM)
  2    FROM xmltest t,
  3         XMLTABLE('//Element' PASSING t.x COLUMNS name VARCHAR2(1000) PATH 'name') y
  4   GROUP BY t.id;

        ID
----------
LISTAGG(Y.NAME,',')WITHINGROUP(ORDERBYROWNUM)
--------------------------------------------------------------------------------
         1
ABC,PQR

There is a function in XPath 2.0, string-join, which will join the string values together with commas. It would seem to be just what you need, but alas it seems Oracle doesn't support it.

来源：https://stackoverflow.com/questions/40025570/oracle-query-using-xpath-to-get-comma-separated-list-for-same-node

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xml

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xpath

oracle11g