Can XPath do a foreign key lookup across two subtrees of an XML?
问题 Say I have the following XML... <root> <base> <tent key="1" color="red"/> <tent key="2" color="yellow"/> <tent key="3" color="blue"/> </base> <bucket> <tent key="1"/> <tent key="3"/> </bucket> </root> ...what would the XPath be that returns that the "bucket" contains "red" and "blue"? 回答1: If you're using XSLT, I'd recommend setting up a key: <xsl:key name="tents" match="base/tent" use="@key" /> You can then get the <tent> within <base> with a particular key using key('tents', $id) Then you