I have 2 QVDs Temp and Temp2. Monthly Amount is in my Temp2 Table. My requirement is, For the Key values found in the Temp table the MonthlyAmount has to be calculated from Termstart to TermEnd Date (i.e to overwrite the Startdate and EndDate values in the Temp2 with TermstartDate and TermEndDate ) The MonthlyAmount for Key Value in the Temp2 remains same..