2. Given the staff relation, write the following relational algebra statements. staff staffNo, fName, IName, position, sex, DOB, salary, branchNo) Return the staff number for the staff member with last name White. Return the first name and salary of everyone who has a salary less than $20,000. Return the first names of staff members who belong to branch B005 or whose name is Susan. Return the staff numbers of staff who are not managers Return the staff numbers of staff who are male and managers. Return the staff numbers of staff who are male or managers