Question

1. Retrieve the SSN and salary of the employee who work for the headquarter department.

2. List all the departments name , the manager’s name of each department and the location of each department.

3. List the last name of each employee whose salary is more than 30,000 and the last name of his/her supervisor

Answer 1

Since your question does not have table structure I am adding this table str and trying to resolve your question:
If you have different table str write your query according else post that table str also.
Thanks in advance.

create table dept
(
dept_no int not null,
dept_name varchar(100) not null,
dept_location varchar(100) not null,
);

create table employee
(
SSN int not null,
emp_first_name varchar(100),
emp_last_name varchar(100),
mgr_emp_id int,
salary int;
dept_no int not null,
primary key (emp_id),
);

create table manager
(
mgr_emp_id int,
mgr_first_name varchar(100),
mgr_last_name varchar(100),
salary int;
dept_no int not null,
)

1. Retrieve the SSN and salary of the employee who work for the headquarter department.
SELECT SSN, salary FROM employee e, dept d
where e.dept_no = d.dept_no
and dept_name = 'headquarter';

2. List all the departments name , the manager’s name of each department and the location of each department.
select
dept.dept_name,
manager.mgr_first_name,
dept.dept_location
from dept, manager
where dept.dept_no=manager.dept_no;

3.List the last name of each employee whose salary is more than 30,000 and the last name of his/her supervisor,
--assuming here supervisior is niothing but manager

Select e.emp_last_name,m.mgr_last_name from employee,manager
where e.mgr_emp_id = m.mgr_emp_id
and e.salary>30000 ;