Adding informations from DSO2 to DSO1

Hi guys,

i am really new in ABAP and need help.

I am loading informations into one DSO and want add also some more informations in the same dso/data range from another dso.

Lets call DSO1,DSO2 and DSO3, keyfield1, keyfield2, field3, field4 and field5

So....

DSO1 has keyfield1 and field3, DSO2 has keyfield2, field4 and field5.

DSO1/field3 = DSO2/keyfield2

So when i do a normal transformation on both I get 2 data sets/lines, one from DSO1 and the other from DSO2 because they have different keyfields.

An idea is to load the data from DSO2 into DSO3 first an read the informations from DSO2 in the end routine of the transformation.

I think it will be with SELECT's but i dont know the right syntax.

Thanks for all helpfull informations.

Regards