在 Oracle 中，如何提取 XML 列中 XML 项的值？

Question

I have XML column in Oracle table where i have this string:

<field name="Text1" type="String"><value/>

I need to extract the value of this field if exists, in the above example it doesn't exists. In the below example the value exists:

<field name="Text1" type="String"><value>12345</value>

What will be the best way to do this?

Thank you.

Answer 1

As you said: extract value .

SQL> with test (col) as
  2    (select '<field name="Text1" type="String"><value>12345</value></field>'
  3     from dual
  4    )
  5  SELECT extractvalue(xmltype(col), '/field/value') result
  6  from test;

RESULT
----------------------------------------------------------------------------------------------------
12345

SQL>

Answer 2

XMLTABLE would be a good choice to use in such a way that

SELECT x.*
  FROM xml_tab t,
       XMLTABLE('//Root'
                   PASSING xml_data
                    COLUMNS
                        field1      INT PATH 'field[@name="Text1"]/value',
                        field2      INT PATH 'field[@name="Text2"]/value'
                        ) x  

returning

FIELD1	FIELD2
12345

where xml_data might be

<Root>
  <field name="Text1" type="String">
    <value>12345</value>
  </field>
  <field name="Text2" type="String">
    <value/>
  </field>
</Root>

Demo

PS. The EXTRACTVALUE function is deprecated. It is still supported for backward compatibility. However, Oracle recommends that you use the XMLTABLE function, or the XMLCAST and XMLQUERY functions instead