How to pass another date parameter value based on Effective Date parameter in HCM Extract

Summary:

Hi All,

There is a requirement where we need to pass a date which should be 31 days before effective date value in HCM extract. For example if effective date is 31-MAR-2023 then another parameter (say lookback date) should pass with value 01-MAR-2023 .

I have tried to achieve it using Refine extract and Post SQL with below query , but its not working . I understand that it can be achieved many other ways like deriving in fast formula or at template level instead of passing value from parameter but considering the scenario this would be best solution if it works . Any suggestion would be highly appreciated.