iv. Calculate the commission earned by Martinez in June. List his name and employee number (name query MartinezJuneCommission). Remember to restrict by 'Martinez' rather than employee number. Note: (1) you will need to join two tables: Sales and Employee; (2) you need to use multiplication (employeecommission* amount as CommissionAmount) and SUM function; (3) you need to use GROUP BY since it is subgroup aggregation for a sales person