Mysql extractvalue函数从xml内容中检索xml片段

Question

My xml content "CommandDefinition" =

<command category="213" id="3" type="om">
    <name>CMD_1</name>
    <description>this is the desc</description>
    <parameter pos_index="1">
        <description>device index</description>
        <state>1</state>
    </parameter>
</command>
<command category="213" id="4" type="om">
    <name>CMD_2</name>
    <description>This parameter belongs to FAPService.{i}.Capabilities.</description>
    <parameter pos_index="1">
        <description>device index</description>
        <state>1</state>
        </parameter>
</command>

I am trying to retrieve entire node value of command tag, where name attribute holds value "CMD_2". i.e. retrieve value should look like:

<command category="213" id="4" type="om">
    <name>CMD_2</name>
    <description>This parameter belongs to FAPService.{i}.Capabilities.</description>
    <parameter pos_index="1">
        <description>device index</description>
        <state>1</state>
        </parameter>
</command>

I tried following:

ExtractValue(CommandDefinition, '//command[name= "CMD_2"]')

But this returns me an empty string instead. Any thought on this? Thx

Answer 1

This link is really helpful: click here! http://www.codeproject.com/Articles/71336/MySQL-XML-User-Defined-Functions?