View-Using SQL
SELECT C.Last_Name, C.First_Name, CE.Event_Date, Ev.Name, Em.Last_Name , Em.First_Name
  FROM Customers C, Customer_Events CE, Events Ev, Employees Em
WHERE C.Customer_ID = :B1
  AND C.Customer_ID = CE.Customer_ID
  AND CE.Event_ID = Ev.Event_ID
  AND CE.Recorded_By = Em.Employee_ID
ORDER BY CE.Event_Date;
•The query seems fine, but you happen to notice that there is no “Employees” table mentioned in the execution plan!
•You look up the Employees definition: