Provide an expression in relational algebra that shows the following query:
Find the names, genders and social security numbers of all employees who have been managers in the last 2 years.
* employee (emp_id,f_name,l_name,dob,ssn,gender,hire_date)
* address (emp_id,street,city,state,zip,country,phone)
* department (dept_id,name)
* emp_in_dept (emp_id,dept_id,begin_date,end_date)
* mgr_of_dept (dept_id,emp_id,begin_date,end_date)
I started with this but I am not sure how to complete the comparing part.
PROJECT f_name, l_name, gender, ssn, (