Union ALL

 
SELECT Employee.S_Code, StaffInfo.dbo.[Staff Details].[Name], 
	ROUND(SUM(TimeSheetDetail.TotalHr), 2) 
	AS AveHoursWork
FROM Employee FULL JOIN
	StaffInfo.dbo.[Staff Details] ON 
	Employee.S_Code = StaffInfo.dbo.[Staff Details].S_Code FULL 
	JOIN
	TimeSheetDetail ON 
	Employee.S_code = TimeSheetDetail.S_code
GROUP BY Employee.S_Code, 
	StaffInfo.dbo.[Staff Details].[Name]
UNION All
SELECT Employee.S_Code, [Name], 
	ROUND(SUM(TimeSheetDetail.TotalHr), 2) AS OTWork, 
FROM TimeSheetDetail LEFT JOIN
	Employee ON TimeSheetDetail.S_Code = Employee.S_code
WHERE TimeSheetDetail.S_Code = Employee.S_Code AND TimeSheetDetail.TimeCode = 2 OR
	TimeSheetDetail.Timecode = 3
GROUP BY Employee.S_Code, [Name]