Do you need the last employee id has 2 different end dates. isn't it

Use this. This will give ur exact output

SELECT x.EmpID,x.StartDate,x.EndDate

FROM(SELECT EmpID,MIN(startdate) AS startdate ,MAX(enddate) AS EndDate FROM Duration where EmpId=3

group by EmpId UNION SELECT EmpID, MIN(startdate),MAX(ISNULL(enddate,Getdate())) As...