store procedure in asp.net

if(@OutTime=null and @InTime!=null)
				begin
			UPDATE       Biometrics
			SET                [Name] =@Name, InTime =@InTime, Userid =@Userid, Group_Id=@Groupid where id=@id
				end
	
			else
			begin
			INSERT INTO Biometrics
	                        ([Name], InTime, Group_Id,Userid)
			VALUES        (@Name,@CheckTime,@Groupid,@Userid)
			end




	select top 1 @id=id from Biometrics where Userid=@Userid  order by id desc 
UPDATE       Biometrics
SET                [Name] = @Name, Group_Id = @Groupid, OutTime = @CheckTime, Duration=DateDiff(mi,@checktime,InTime)  where  id=@id

i have put if..else condition in my storeprocedure.but data in if is not fire.every time else condition is fire.i think i have mistack in

if(@OutTime=null and @InTime!=null)

second problem is datediff function. duration is comming but wrong difference is comming.what is solution for that.Everything is working fine except this two thing.So i have not any error in my code.

Tags: C#, ASP.NET