Given the following simplified XML instance, can
anyone suggest an expression that will return
ONLY the 'Value' node containing <enum> children
with values A, B and C. I can't rely on the name
of the parent node of <Value> hence I have
deliberately named these as UnknownNameX or any other intervening structure.

<Trade>
        <UnknownName1>
                <Value>
                        <enum>A</enum>
                        <enum>B</enum>
                        <enum>C</enum>
                </Value>
        </UnknownName1>
        <UnknownName2>
                <Value>/Trade//Value[ancestor::Trade]</Value>
        </UnknownName2>
        <Treatment>
                <UnknownName3>
                        <Value>
                                <enum>D</enum>
                                <enum>E</enum>
                                <enum>F</enum>
                        </Value>
                </UnknownName3>
        </Treatment>
</Trade>

/Trade//Value        - returns all 3 <Value> nodes
/Trade//Value[1]    - also returns all 3 <Value> nodes (why is that ?)
/Trade//Value[2]    - returns nothing (why is that ?)

A number of people have responded already, but
from what I can tell, the two that have supplied
suggested replacements haven't acknowledged that
the <Value> elements are at different depths of
the tree.  I note that the third <Value> is at
level 4 while the other two are at level 3.

So, I suggest that the following will get you the
first <Value> in the document regardless of the depth of the element:

Hugh explained why your prior attempts don't work
... my wording for this is as follows: //Value[1]
won't work because the predicate is bound at the
step level so "//" looks through the entire
document and "Value[1]" which is an abbreviation
for "child::Value[1]" returns the first child
named "Value", so the combination returns "the
first child named Value at every level of the document".

This is a trick question I have had in my
hands-on XSLT training class since 1999 when it
was still combined with DSSSL training.  I've
also see it at conferences where vendors post it
on a white board as a "challenge" to stylesheet
writers to determine who knows their XPath and who doesn't.

--
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