Hello All   I have a table as follows   ID : The ID is Unique value in the sense for a set of rows it will remains same , but the table may contain ID1, ID2,ID3,…IDn varies from case to case Time : I have only 4 Values in the Table , Time1, Time2, Time 3 and Time4 Group : I have n different Groups starting from Grp1, Grp2, Grp3,…,Grpn from case to case TimeDiff: Each row will be having a value and may vary from 0 to 123456789   Have ID Time Group TimeDiff ID1 Time1 Grp1 12371231 ID1 Time1 Grp1 12371231 ID1 Time2 Grp1 54934 ID1 Time2 Grp1 10543254 ID1 Time2 Grp2 1776401 ID1 Time2 Grp2 1776 ID1 Time3 Grp3 9 ID1 Time2 Grp3 522 ID1 Time4 Grp3 0 ID1 Time3 Grp2 13046 ID1 Time3 Grp1 167599 ID2 Time3 Grp1 4990 ID2 Time3 Grp3 0 ID2 Time2 Grp1 11762618 ID2 Time2 Grp3 0 ID2 Time2 Grp2 590 ID2 Time4 Grp3 0 ID2 Time3 Grp2 19738 ID2 Time1 Grp1 11787936   I want to sum the TimeDiff if the Group having same value and Time having same value for each ID   Have   Want ID Time Group TimeDiff   ID Time Group TimeDiff ID1 Time1 Grp1 12371231   ID1 Time1 Grp1 24742462 ID1 Time1 Grp1 12371231   ID1 Time2 Grp1 10598188 ID1 Time2 Grp1 54934           ID1 Time2 Grp1 10543254               Bellow should be the final table   Want ID Time Group TimeDiff ID1 Time1 Grp1 24742462 ID1 Time2 Grp1 10598188 ID1 Time2 Grp2 1778177 ID1 Time2 Grp3 522 ID1 Time3 Grp3 9 ID1 Time3 Grp2 13046 ID1 Time3 Grp1 167599 ID1 Time4 Grp3 0 ID2 Time1 Grp1 11787936 ID2 Time2 Grp1 11762618 ID2 Time2 Grp3 0 ID2 Time2 Grp2 590 ID2 Time3 Grp1 4990 ID2 Time3 Grp3 0 ID2 Time3 Grp2 19738 ID2 Time4 Grp3 0 ... View more