> Yes, ROW has only 1 COB_ID.
> 
> How can I set XPATH version?

You just need to find an XPath or XSLT processor that supports version 2.0.
For most people that means using Saxon, but there are others. I don't think
you told us whether you were using XPath within XSLT, or free-standing
XPath.

Michael Kay
http://www.saxonica.com/