SQL & PL/SQL :: Designing A Query - Who To Loop Through Process

i have query which scores a customer details on some factors and gives it a rank/I have a table called agents which holds the agents details.

This is how i get the rank:
select *
from (
select customer_name ,agent_number

[code]....

The agents table has agent_number and agent_Name....By the above query i check various score against all available agents and assign customers to agents who have highest score or rank is 1

But my problem is who to loop through the process.. i mean after the intial customers are assinged with agents it should run again for remaining customers and for agents who are free(and rank for them is 1) should be checked for assignment Once all agents are assigned but still more customers are available then agents even thoug they are already assigned they can be assigned now since no agent is free..