Specify relational expressions for the following descriptions on the database schema shown in Figure 3.5 using the relational operators discussed in this chapter. Also show the result of each query if applied to the database of Figure 3.6.

For each department, retrieve the department name, and the average salary of employees working in that department.

Tip: Grouping

Retrieve the average salary of department 5 employees.

List the last names of department managers who have dependents.