ONLY QUESTIONS 14,15,16,17,18,19 needed others not needed

Tables are: prereq, time_slot, advisor, takes, student, teaches, section, instructor, course, department and classroom some of which may not be necessary in the below tasks.

11. Print the names of any two instructors (two columns) having the same salary. 12. Print the names of the students from a department with least budget. 13. Change the salary of instructor Wu to 600 without dropping anything from the database and reverting changes, if any. 31 2009 and 2010 with a single query USE NESTED SUBQUERIES ONLY!!! Make this 14. Create an object which generates integer numbers which will upon 7th call return 15. List all students from Physics department and number of their courses taken in query a view. 16. Compose two different (different sources) scripts that shows whether a table (for ex., STUDENT) column can take NULL values or not 17. Invalidate a synonym that depends on a view that itself depends on a table 18. Print names of students and courses he/she takes. If a student doesn't take a course, it must be in the output as well but course name must be 'Not Registered'. 19. Query to see if anything depends on the given view. 11. Print the names of any two instructors (two columns) having the same salary. 12. Print the names of the students from a department with least budget. 13. Change the salary of instructor Wu to 600 without dropping anything from the database and reverting changes, if any. 31 2009 and 2010 with a single query USE NESTED SUBQUERIES ONLY!!! Make this 14. Create an object which generates integer numbers which will upon 7th call return 15. List all students from Physics department and number of their courses taken in query a view. 16. Compose two different (different sources) scripts that shows whether a table (for ex., STUDENT) column can take NULL values or not 17. Invalidate a synonym that depends on a view that itself depends on a table 18. Print names of students and courses he/she takes. If a student doesn't take a course, it must be in the output as well but course name must be 'Not Registered'. 19. Query to see if anything depends on the given view