//zad 1 a

select first_name,last_name from EMPLOYEES where emp_no IN (select emp_no from salaries  where salary IN (select max(salary)from salaries));

//zad 1 b
select first_name,last_name from EMPLOYEES where emp_no IN (select emp_no from salaries  where from_date IN (select min(from_date)from salaries));

//zad 2
SELECT first_name,last_name FROM employees where (hire_date < (select max(from_date) from dept_manager));

//zad 3


select distinct emp_no from salaries where salary >(select avg(salary) from salaries where to_date <='01-Jan-00');

//zad 4
select dept_name from departments where dept_no IN (select dept_no from dept_manager where emp_no IN(select distinct emp_no from dept_emp where emp_no IN (select emp_no from salaries where salary>90000)));


//zad5
select first_name,last_name from employees where emp_no IN(select emp_no from dept_emp where dept_no IN(select dept_no from dept_emp where emp_no IN (select emp_no from EMPLOYEES where last_name ='Luck')));


//zad6
select first_name, last_name from employees where emp_no IN (select emp_no from DEPT_EMP where (TO_DATE-from_date) in (select min(to_date-from_date) from  dept_emp));

//zad 7
SELECT COUNT (gender) from EMPLOYEES where gender='M' union
SELECT COUNT (gender) from EMPLOYEES where gender='F';

//

SELECT GENDER, COUNT(*) FROM EMPLOYEES GROUP BY GENDER;
//zad8
SELECT COUNT (gender) from EMPLOYEES where gender='M' and emp_no IN (select emp_no from dept_emp where dept_no ='d006')  union
SELECT COUNT (gender) from EMPLOYEES where gender='F' and emp_no IN (select emp_no from dept_emp where dept_no ='d006') ;

//zad9
select count(emp_no) from titles where FROM_DATE <='01-JAN-00' and title IN (select title from titles where title='Engineer');


//zad10
SELECT DEPT_NO, COUNT(*) FROM DEPT_EMP GROUP BY DEPT_NO HAVING COUNT(*)<100 ;