Database Systems 6th Edition by Ramez Elmasri, Shamkant B. Navathe

تمرين 2

-Specify the following queries on the COMPANY relational database schema shown in Figure 3.5, using the relational operators discussed in this chapter. Also show the result of each query as it would apply to the database state of Figure 3.6.
(a) Retrieve the names of employees in department 5 who work more than 10 hours per week on the 'ProductX' project.
(b) List the names of employees who have a dependent with the same first name as themselves.
(c) Find the names of employees that are directly supervised by 'Franklin Wong'.
(d) For each project, list the project name and the total hours per week (by all employees) spent on that project.
(e) Retrieve the names of employees who work on every project.
(f) Retrieve the names of employees who do not work on any project.
(g) For each department, retrieve the department name, and the average salary of employees working in that department.
(h) Retrieve the average salary of all female employees.
(i) Find the names and addresses of employees who work on at least one project located in Houston but whose department has no location in Houston.
(j) List the last names of department managers who have no dependents.