Error while using if else in where clause

I am passing two variables like SDate and EDate to stored procedure and I want select data from table whereVDate is betwwen SDate and EDate if both SDate and EDate is not null .If EDate is null then I want to select data where VDate = SDate.I have tried using If..Else andCase in where clause but it was giving incorrect syntx error. Query :

SELECT
    Column1 ,column2fromTable twhere t.VDate IN(If EDate ISNOTNULLSELECT
        VDate FROMTablewhere VDate BETWEEN SDate AND EDateELSE
     SDate)

Any help would be appreciated.