Custom Payroll Flow Pattern : Post SQL Bind isn't fetching data

Hello -

Trying to leverage the advantage of Post SQL Bind at "Task" Level. Defined a custom flow parameter as "FF_NAME" , Display - Mandatory, Type - Text.

The User will pass the Fast Formula Name as Input Parameter while submitting the flow. So, at Task Level, have used Post SQL Bind. But, System is not able to fetch or evaluate the SQL query. It is always returning the "Blank" value.

Post SQL Bind Code :

SELECT to_char(formula_id) FROM fusion.ff_formulas_vl, pay_flow_param_values fpv2, pay_flow_parameters fp2 WHERE formula_name = fpv2.flow_param_value AND fpv2.flow_instance_id (+) = :pflowinstanceid AND fpv2.base_flow_parameter_id (+) = fp2.base_flow_parameter_id AND fp2.base_flow_parameter_name = 'FF_NAME'