Ranking Function is the bassically use for the return value which is the ranking of the each row in the partion. These ranking functins are non Deterministic. there are many diff type of ranking functions :
> ROW_NUMBER() OVER([<Partion_By_Clause>]<Order_By_Clause>)
> RANK() OVER([<Partion_By_Clause>]<Order_By_Clause>)
> DENSE_RANK() OVER([<Partion_By_Clause>]<Order_By_Clause>)
