Dear ,
It is very useful to have knowledge of SAP now a days. I have an experience of 6-7 years working in SAP. It is being seen that it will be better if we have enough knowledge of FI and MM Module. Why? Because on the basis of MM module and FI module all other things are inter related till balance sheet items. It is CO module which will help for cost control and budgetory control.
how it works...
first PR is made
then PO is made.... (PO contains all details like what is GL, what is cost center or wbs element)
then GRN is made for material part (system will pick GL and cost centre from PO itself)
during this process, one temporary account (named as GRIR account )is created and it is credited
then finally it is to be posted by account payable people (at this time ,GRIR account will be debited
now after posting entry by AP person, actual vendor account is credited then we can go for payment.
this is the normal procedure which is being followed when there is any PO.
As now a days more and more companies are going on SAP , it is advantageous to go for it...at the same time i would also like to tell first fix your goal whether you want to go for practice or for job. If you wish to go for job, then it is okay, otherwise what i prefer that if will be better if you get enough knowledge of how SAP works...
hope it will worth for you.
thanks