Advanced XPath Q: Select tags not having a sibling

[Harald Groven]

Is the Mysql implementation of EXTRACTVALUE able to select tags not having certain sibling tag?

I have a huge XML data set derived from the XTM (TopicMap) standard. I want use the EXTRACTVALUE function to get the content of all the <baseNameString> tags which do not have a <scope> tag as sibling.


<topic>
<baseName>
<scope>
<topicRef xlink:href="1" />
</scope>
<baseNameString> I dont care about this element </baseNameString>
</baseName>
<baseName>
<baseNameString> THIS IS THE ELEMENT I WANT TO SELECT! </baseNameString>
</baseName>
<baseName>
<scope>
<topicRef xlink:href="111" />
</scope>
<baseNameString> I dont care about this data either ... </baseNameString>
</baseName>
</topic>

These Xpaths will not work:

EXTRACTVALUE(xmldata, '//baseName/baseNameString') # also selects with the unwanted <scope> sibling

EXTRACTVALUE(xmldata, '//baseName/baseNameString[1]') # won't work if the baseNameString without scope sibling i #2 or #3

EXTRACTVALUE(xmldata, '/topic/baseName/scope/../baseNameString') # selects the disjunct set of baseNameString cp. the desired ones

EXTRACTVALUE(xmldata, '/topic/baseName/baseNameString | /topic/baseName/scope') # only selects if the element without the <scope> sibling is first