After MBA; Should I join as Clerk in SBI Hyderabad?

I am MBA Marketing working in Marketing Department of a Company at Mumbai;
My current sallary is about 20000/-
I got an order of selection in SBI as Clerk,
Please guide me to take decision.
Should I join as Clerk?
What will be the future as Clerk in SBI?
What are the Promotional Policies of SBH(SBI)?
Please help.
Thanks in advance