Oracle 查询以动态地从表中提取 XML 元素值

Question

我正在寻找可以在具有存储 XML 的列之一的表上运行的 Oracle 查询。此查询应动态采用查询中的 xpath 以从所有节点中提取字符串。 我在下面尝试过，但我必须对 xpath 进行硬编码。 我不想对 xpath 进行硬编码。

有没有一种方法可以根据 XML 的结构（结构可能会有所不同）动态生成 xpath 以提取 xml 节点值？

我需要的输出是 xml 节点的提取值。

我试过：

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

将包含动态路径的表与包含 XML 的表连接起来，然后使用XMLTABLE提取值：

甲骨文设置：

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;

查询 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

查询 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;

查询 3 ：

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

输出：

\n身份证 | 路径 | 价值\n -: |  :----------------------------- |  :----\n  1 |  /报告/fulcriteria |  1    \n  1 |  /报告/conumb |  2    \n  1 |  /报告/复制|  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<> 在这里摆弄