Optimize the following SQL Query by using Query Tree and Heuristic Rules: SELECT C.Fname, E.Fname FROM Employee AS E, Customer AS C, Order AS O WHERE E.EMP_ID=O.E_ID AND C.City='Jeddah' AND C.Customer_ID=O.C_ID AND E.EMP_ID='12943'

The query optimizer constructs an initial query tree using join, selection, and projection operations. (a) True (b) False

Write an SQL query to display the total salary of each employee adding the Salary with Variable value.

Question: Which colleges offer courses?    (Change the SQL query to an relational algebra query.) **Please show the resulting tuples output based on your answer as well in a table for further explanation.  ** SELECT COURSE.COLLEGE FROM COURSE, DEPARTMENT WHERE COURSE.DCODE = DEPARTMENT.DCODE;