在Oracle中选择xml元素值 [英] Select xml element value in Oracle

问题描述

我正在尝试从位于Oracle表的XMLTYPE列中的xml元素中提取值.我尝试提取的xml元素有一个为其定义了名称空间的父级. xml看起来像:

I am trying to extract a value from an xml element, located in an XMLTYPE column in an Oracle Table. The xml element which I am trying to extract have a parent for which a namespace is defined. The xml looks something like:

<a>
  <b xmlns="urn:www.someSite.com/myModel">
    <c>my value</c>
  </b>
</a>

如果我要提取"a"元素的内容，则会正确返回其上下文:

If I want to extract the content of the "a" element, its context is correctly returned:

SELECT Extract(myColumn, '/a') FROM myTable;

但是对于返回"c"元素的内容，我没有成功找到任何可用的版本.以下说明不起作用:

But for returning the content of the "c" element I didn't succeed to find any version to work. The following instructions does not work:

SELECT Extract(myColumn, '/a/b/c') FROM myTable;

SELECT Extract(myColumn, '/a/b/c', 'xmlns="urn:www.someSite.com/myModel"') FROM myTable;

SELECT Extract(myColumn, '/a/b/c', 'urn:www.someSite.com/myModel') FROM myTable;

有人可以在这种情况下起作用的提取语句来帮助我吗?

Can anybody help me, with the extract statement that would work in this case?

推荐答案

由于a元素没有名称空间，因此您可以先提取其子元素，而无需在函数中使用名称空间，然后从b，其名称空间为:
试试:

Since the a element does not have the namespace, you can first extract its child elements without using namespaces in the function, and then extract the value from the b with the namespace:
Try:

select extract(extract(myColumn, 'a/*'),
               'b/c/text()',
               'xmlns=urn:www.someSite.com/myModel') 
  from myTable

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