@judeniroshan, the main problem here is that this data definition does not have an appropriate editor associated with it. That's why the "sql" property is showing up as it is and there is no way to add parameters directly. For example, compare this UI with the one for a Sql Cohort Definition.
I went ahead and committed a small enhancement so that the appropriate SQL definition editor is used here. As long as I was in there, I also modified the preview functionality so that it should show results for Sql Data Definitions by running them against a random cohort of 50 patients.
Here is the ticket I worked against: https://issues.openmrs.org/browse/REPORT-814
Give things a shot running against master of reporting and let me know how things work out.