Hi Shanmuk,
SAP is not based on your degree, it is based on your Industry experience.
A Mechanical Engineer can work as Production Engineer, Maintenance team, Service team, Warehouse etc.
Since your experience will not relate to any functional modules like Production Planning, Plant Maintenance, Customer Service or Materials Management, you can opt for BI / BW (very less coding and complete designing). You will be report to develop reports based on the data from SAP and other sources.
All the Best
Regards
Terence