Timediff from one status to another

Content

Hi,

I am trying to get the time taken from one status to another.

Ex: Need to know what is the time taken from to be reviewed to Initiate ability test

	From	To
Step Name	Under Review	Assessment
Status Name	To Be Reviewed	Initiate Ability Test

Tried below and couldn't succeed. Kindly help.

MIN(TIMESTAMPDIFF(SQL_TSI_DAY,(CASE "Submission CSW Status - Historical"."Historical Status Name" WHEN 'To Be Reviewed' THEN "Submission CSW Status - Historical"."Submission Historical Status Start Date" END),(CASE "Submission CSW Status - Historical"."Historical Status Name" WHEN 'Initiate Ability Test' THEN "Submission CSW Status - Historical"."Submission Historical Status Start Date" END)))