A recent CA PPM flipboard magazine feature article explains a construct that can be used in the WHERE clause that allows the portlet to retrieve a name-value pair from the XML page URL where you placed your user-defined portlet. It is called an XPATH or XML parameter construct. This construct can only be used on a specific portlet instance type and not on the General portlet instance type.
See How to Use the XPATH XML Parameter in NSQL Constructs | CA Clarity PPM Cookbook.
-Damon Logiudice
CA PPM Information Services