XPath: Select parent nodes which have a subnode with an attribute

Question

I want to get the "Package" nodes which have a "System" grandchild with an "mtm" attribute, and the value of the "mtm" attribute is "2055". For the below example document, only the first Package node should be returned.

I use

"/Database/Package[/SystemCompatibility/System[@mtm='2055']]"

but it does not work. What is wrong with this expression?

<?xml version="1.0" encoding="UTF-8"?>
<Database version="300">
<Package id="6imb05ww" description="ThinkPad Modem Adapter">  
    <SystemCompatibility>
        <System mtm="8742" os="Windows XP" oslang="en" />
        <System mtm="2055" os="Windows XP" oslang="jp" />
    </SystemCompatibility>
</Package>
<Package id="6imb06ww" description="ThinkPad Modem Adapter">  
    <SystemCompatibility>
        <System mtm="3046" os="Windows XP" oslang="en" />
    </SystemCompatibility>
</Package>
</Database>

Solution 1

Remove the / before SystemCompatibility

/Database/Package[SystemCompatibility/System[@mtm='2055']]

Solution 2

Try using:

/Database/Package/descendant::System[@mtm='2055']

Using the descendant:: operator will allow you to get any System grandchild of Package. http://www.w3schools.com/xpath/xpath_axes.asp

Comments

[John Giotta]

This will return only the System node and not the entire Package node

[kennyzx]

It works, thanks. My bad, i thought i have tried this approach but actually i didn't.

[cookie_monster]

Ah, you're right. I misunderstood the question. Thanks for pointing that out.

[John Giotta]

This would work with some modification! Note the encapsulating brackets /Database/Package[descendant::System[@mtm='2055']]

[cookie_monster]

I was just testing that exact code out to make sure it would work, but you beat me to getting it posted. Thanks for posting the correction too!