Consider the following relational schema:  

Employee (`underline(empId)`, empName, empDept)

 Customer (`underline(custId)`,custName, salesRepId, rating) 

SalesRepId is a foreign key referring to empId of the employee relation. Assume that each
employee 

makes a sale to at least one customer. What does the following query return? 

 SELECT empName 

 FROM employee E 

WHERE NOT EXISTS (SELECT custId

                                       FROM customer C

                                      WHERE C. salesRepId = E. empId 

                                      AND C. rating < > 'GOOD')