How to add multiple columns of internal table

Hi Friends,

I am joining 2 tables and stores the value in an internal table.

the structure of the final internal table is as follows.

ZPROJID   ZCOST  ZDEF ZEFF
TEST1       10           20     30

TEST1       10           20     30

TEST1       10           20     30

TEST2       20           20     30

TEST2       20           20     30

TEST2       20           20     30

Now I have add ZCOST ZDEF and ZEFF for each project id

I need the output like

ZPROJID   ZCOST  ZDEF ZEFF

TEST1         30          60      90

TEST2         60          60      90.

how to add multiple columns based on ZPROJID.

Thanks for your help.

Regards,

Vijay.