-- Tables Structure:

create table employee
( emp_ID int primary key
, emp_NAME varchar(50) not null
, DEPT_NAME varchar(50)
, SALARY int);

insert into employee values(101, 'Mohan', 'Admin', 4000);
insert into employee values(102, 'Rajkumar', 'HR', 3000);
insert into employee values(103, 'Akbar', 'IT', 4000);
insert into employee values(104, 'Dorvin', 'Finance', 6500);
insert into employee values(105, 'Rohit', 'HR', 3000);
insert into employee values(106, 'Rajesh',  'Finance', 5000);
insert into employee values(107, 'Preet', 'HR', 7000);
insert into employee values(108, 'Maryam', 'Admin', 4000);
insert into employee values(109, 'Sanjay', 'IT', 6500);
insert into employee values(110, 'Vasudha', 'IT', 7000);
insert into employee values(111, 'Melinda', 'IT', 8000);
insert into employee values(112, 'Komal', 'IT', 10000);
insert into employee values(113, 'Gautham', 'Admin', 2000);
insert into employee values(114, 'Manisha', 'HR', 3000);
insert into employee values(115, 'Chandni', 'IT', 4500);
insert into employee values(116, 'Satya', 'Finance', 6500);
insert into employee values(117, 'Adarsh', 'HR', 3500);
insert into employee values(118, 'Tejaswi', 'Finance', 5500);
insert into employee values(119, 'Cory', 'HR', 8000);
insert into employee values(120, 'Monica', 'Admin', 5000);
insert into employee values(121, 'Rosalin', 'IT', 6000);
insert into employee values(122, 'Ibrahim', 'IT', 8000);
insert into employee values(123, 'Vikram', 'IT', 8000);
insert into employee values(124, 'Dheeraj', 'IT', 11000);

-- select * from employee;

-- Query 2:
-- Write a SQL query to fetch the second last record from a employee table.

-- select emp_id, emp_name, dept_name, salary from (
--     select *, row_number() over() as rn from employee order by emp_ID desc
--     ) as ordered_employee 
-- where 
--     rn = 2;
    
/* Write a SQL query to display only the details of employees who either earn the highest salary
or the lowest salary in each department from the employee table.
*/

-- Query 3:

-- Write a SQL query to display only the details of employees who either earn the highest salary
-- or the lowest salary in each department from the employee table.

select x.* from employee e join (
    select *,
    min(SALARY) over(partition by DEPT_NAME) as min_salary, 
    max(SALARY) over(partition by DEPT_NAME) as max_salary
    from employee
) as x
on e.emp_ID = x.emp_ID
and (e.salary = x.min_salary or e.salary = x.max_salary)
order by x.DEPT_NAME, x.salary