Enhancement code for Partner function

Dear Experts,

Please help me with a code to populate two fields added in the append structure. The fields to be populated are ZZORDADD & ZZINVPRBY.

The Table which contains the data is WYT3.

The fields in the table of concern are LIFNR & PARVW. The datasource is 0VEN_PURORG_ATTR.

The field LIFNR has all the vendors and PARVW has partner function data such as OA & PI.

The logic is that if PARVW is OA then ZZORDADD should be the corresponding LIFNR

and if PARVW is PI then ZZINVPRBY should be the corresponding LIFNR.

e.g table WYT3 data is

LIFNR  PARVW

1001      OA

1002      OA

1003      PI

1004      OA

1005      PI

then datasource should have

LIFNR  ZZORDADD (THE OA vendors)  ZZINVPRBY( The PI vendors)

1001     1001

1002     1002

1003                                                      1003

1004     1004

1005                                                      1005

Please advice on the enhancement code to be written as my ABAP skills are not so good.

Thanks a lot for your help.

Kind Regards,

Kshama.