Hi Samique,
This Question is certainly different....
You need to know the basics of ABAP...The more you know ABAP the Better it is..Always ABAP would be preferred in BW and SQL in HANA...going forward....
However i would like to classify it this way...
Least:-
To Read the Code...say its Statement...understand what has been written.Write Field Routine and What are the types of Code and where all that can be written ....
Medium:-
To write few Select Statements,Read,Loop Statements,Understand Performance Related Optimized Coding Principles...Familiar with Start,Field Routine and End Routine.
High:-
Write Function Module,programs,Expert Routine,BADI..OOPs based ABAP...may be it goes on..
Hope it gives an Idea...
Regards
SVU