--1
SELECT d.department_name FROM HR..departments d, HR..employees e, HR..jobs j
    WHERE e.department_id = d.department_id
    AND e.job_id = j.job_id
    AND j.max_salary > 25000
GROUP BY d.department_name

--2
SELECT c.country_id,
    (SELECT SUM(e.salary) FROM HR..employees AS e, HR..departments AS d, HR..locations AS l
     WHERE e.department_id = d.department_id
     AND d.location_id = l.location_id
     AND l.country_id = c.country_id)
FROM HR..countries AS c

--3


--4
IF EXISTS (SELECT 1 FROM sys.objects WHERE TYPE='P' AND NAME = 'podwyzka')
    DROP PROCEDURE podwyzka
GO

CREATE PROCEDURE podwyzka @idDzialu INT, @procentPodwyzki INT AS
BEGIN
    DECLARE @Liczba_podwyzek INT;
    UPDATE HR..employees
    SET salary=salary*@procentPodwyzki/100 + salary
    FROM HR..jobs
    WHERE employees.salary = jobs.min_salary AND employees.department_id = @idDzialu
    SET @Liczba_podwyzek = @@ROWCOUNT

    DECLARE @PrintMessage varchar(50);
    IF @Liczba_podwyzek = 0
        SET @PrintMessage = 'Nie ma takich pracownikow'
    ELSE
        SET @PrintMessage = 'Podwyzszono zarobki ' + STR(@Liczba_podwyzek) + ' pracownikom'
    PRINT @PrintMessage
END
GO

EXEC podwyzka 60, 15