mlm left and right side commission

i am using php and mysql mlm table i want to generated left right sum of amount this is my table table name is investment `Invested_user` means user id means member name `uplink` id means who is upline who is sponsor `xleft` means left side `xright` means right side `invest_amount` i want to sum invest_amount left and right side here is some example data ============================= Monir- Jamal - L 4000 Jahir -Jamal - R 2000 Jasim -Monir - R 1000