Super key is super set of attributes forming a key, primary key is the exact set of attributes which serve the purpose of identifying any tuple in a relation while a candidate key is any set of attributes which has the unique property, and they can be a primary key. Basically a primary key is also first a candidate key, there can be several candidate keys in a relation, among which one primary key can be choosen to identify the tuples in the relation… while taking super set of any of the candidate key makes it a super key.
Super key is super set of attributes forming a key, primary key is the exact set of attributes which serve the purpose of identifying any tuple in a relation while a candidate key is any set of attributes which has the unique property, and they can be a primary key. Basically a primary key is also first a candidate key, there can be several candidate keys in a relation, among which one primary key can be choosen to identify the tuples in the relation… while taking super set of any of the candidate key makes it a super key.