Dear all, I would like to do a simple sum per salesid in php - mysql after cross calculation between date (2 table) to get the real time commission, all the value already come out correctly but I got problem with final sum per sales id. salesid-commission aa0001 - 1000 bb0001 - 500 aa0001 - 200 bb0001 - 50 I already try with few sample in this web but still cannot meet the correct result. I cannot do the sum in mysql because of some reason (need calculation with other table) the result will be: aa0001 - 1200 bb0001 - 550 I aprreciated for any help to complated the test. Thank you so much.