Right now the AF Link Table Query does not have elegant way of specifying the optional parameters in the call to Stored Procedures. Therefore, if an optional parameter occurs before mandatory parameter, then the optional parameter has to be supplied value "null" in the query string itself. It would be elegant, if only the parameter name could be specified in the query string (just like for mandatory parameter) and in the parameter table, its default value set to "null" (or kept empty, which would automatically be then read as "null").
