Hi, Please try this,
SELECT [Sno],[CompanyID],[BranchID],[Date],[Day],'YES' as [WorkingDay], '--' as [Occasion] FROM tblWorkingDayList
Union all
Select [Sno],[CompanyID],[BranchID],[Date],[Day],'NO' as [WorkingDay], [Occasion] FROM tblHolidayList
Order by date
and update -- Good luck