Imagine you have a database with a customers table consisting of the following:

First 5 rows of customers table, ordered by id

id      name             city          grade   salesperson_id
------  ---------------  ------------  ------  --------------
3001    Brad Guzan       London        100     5005          
3002    Nick Rimando     New York      100     5001          
3003    Jozy Altidore    Moscow        200     5007          
3004    Fabian Johns     Paris         300     5006          
3005    Graham Zusi      California    200     5002