Hi, for that you'll have the use the GQIDMS class in your ad hoc data source.

With that class you can request the parameter value (or subscribe to it to provide updates), and return it as a single row in your GQI result.

Note: you can also retrieve the value through GQI by using the built-in Get parameters for elements where filtered on element ID, saves you the time and effort to create your ad-hoc data source.