PART 2 (Multiple Tables) (50 marks) (10) Explain the purpose of a JOIN in SQL and the difference between a left JOIN and an Inner join. (5 marks) Aircraft aid INT a_name VARCHAR(45) crusgrange INT Certified_e_id INT Certified_A_id INT Employee e_d INT esame VARCHAR(45) salary INT Inden Aircraft Certified fi_Employee_Certified Certified Ted NT a DENT Landes There is a relationship between the Employee, Certified and Aircraft tables as shown in the ERD diagram. Implement these changes in the SQL. (11)Explain the changes you have made and and why. (15 marks) (12)Write the SQL to display the list of employees and the aircraft that they are certified to fly. (10 marks) (13)Mary Johnson has decided to leave the company. What SQL would you use to determine her employee number.? (10 marks) (14) What SQL would you use to delete Mary Johnson from database. Explain the steps you would follow to remove Mary Johnson from the database. Describe the options that would be available to you and explain the implications for the database and referential Integrity (10 marks)