Null Value then '' should be shown

Hi

I have below select statement . I want if ResubmitDate - SentBackdate is null then "" should be shown

(select DATEDIFF(d,Min([SentBackDate]),Max([ReSubmitDate])) from [PRQS].[dbo].[View_Capex_StepWiseApprovalDetail] where EntryCode=L.[PR] ),
 

Thanks