Oracle 查询以动态地从表中提取 XML 元素值

Question

I am looking for Oracle query which can be run on a table that has one of the column storing XML's This query should dynamically take the xpath in the query to extract the string from all nodes. I have tried below but i have to hardcode the xpath. I do not want to hardcode the xpath.

Is there a way to generate the xpath, based on the structure of XML(structure may vary) on the fly to extract the xml node value?

Output i need is the extracted value of the xml node.

I tried:

SELECT xmltype(XMLCOLUMN).EXTRACT('/report/fulcriteria/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/conumb/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/dup/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/reportdup[1]/dupsource/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/reportdup[2]/dupsource/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/reportdup[2]/dupnumb/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/reportdup[3]/dupsource/text()'),
       xmltype(XMLCOLUMN).EXTRACT('/report/reportdup[3]/dupnumb/text()') . 
       xmltype(XMLCOLUMN).EXTRACT('/report/final/dup/text()'),
  FROM MYTABLE

Answer 1

Join the table containing your dynamic paths with the table containing the XML and then use XMLTABLE to extract the value:

Oracle Setup :

CREATE TABLE mytable ( id, xmlcolumn ) AS
SELECT 1, '<report>
  <fulcriteria>1</fulcriteria>
  <conumb>2</conumb>
  <dup>3</dup>
  <reportdup><dupsource>4.1</dupsource></reportdup>
  <reportdup><dupsource>4.2a</dupsource><dupnumb>4.2b</dupnumb></reportdup>
  <reportdup><dupsource>4.3a</dupsource><dupnumb>4.3b</dupnumb></reportdup>
  <final><dup>5</dup></final>
</report>' FROM DUAL;

CREATE TABLE paths ( path ) AS
SELECT '/report/fulcriteria' FROM DUAL UNION ALL
SELECT '/report/conumb' FROM DUAL UNION ALL
SELECT '/report/dup' FROM DUAL UNION ALL
SELECT '/report/reportdup[1]/dupsource' FROM DUAL UNION ALL
SELECT '/report/reportdup[2]/dupsource' FROM DUAL UNION ALL
SELECT '/report/reportdup[2]/dupnumb' FROM DUAL UNION ALL
SELECT '/report/reportdup[3]/dupsource' FROM DUAL UNION ALL
SELECT '/report/reportdup[3]/dupnumb'  FROM DUAL UNION ALL
SELECT '/report/final/dup' FROM DUAL;

Query 1 :

SELECT t.id,
       p.path,
       x.value
FROM   MYTABLE t
       CROSS JOIN PATHS p
       CROSS JOIN XMLTABLE(
         p.path
         PASSING XMLTYPE( t.xmlcolumn )
         COLUMNS
           value VARCHAR2(4000) PATH '.'
       ) x

Query 2 :

SELECT t.id,
       p.path,
       XMLQUERY(
         (p.path || '/text()')
         PASSING XMLTYPE( t.xmlcolumn )
         RETURNING CONTENT
       ) AS value
FROM   MYTABLE t
       CROSS JOIN PATHS p;

Query 3 :

SELECT t.id,
       p.path,
       XMLTYPE( t.xmlcolumn ).EXTRACT(p.path||'/text()').getStringVal() AS value
FROM   MYTABLE t
       CROSS JOIN PATHS p;

Output :

\nID | PATH | VALUE\n-: |  :----------------------------- |  :---- \n 1 |  /report/fulcriteria |  1     \n 1 |  /report/conumb |  2     \n 1 |  /report/dup |  3     \n 1 |  /report/reportdup[1]/dupsource |  4.1   \n 1 |  /report/reportdup[2]/dupsource |  4.2a  \n 1 |  /report/reportdup[2]/dupnumb |  4.2b  \n 1 |  /report/reportdup[3]/dupsource |  4.3a  \n 1 |  /report/reportdup[3]/dupnumb |  4.3b  \n 1 |  /report/final/dup |  5     \n

db<>fiddle here