create or replace procedure zad1(rocznik student.rok%type, srednia integer)
is
    sredniaStudenta integer;
    wszystkieOceny integer;
    idStudent integer;
    rokStudenta student.rok%type;
    cursor Cur_zad1 is select idstudenta from ocena;
begin
    open Cur_zad1;
    loop
        fetch Cur_zad1 into idStudent
        exit when Cur_zad1%NOTFOUND;

        select rok
        into rokStudenta
        from student
        where idstudenta = idStudent;

        if rokStudenta = rocznik
        then
            select sum(wartosc)
            into wszystkieOceny
            from ocena
            where idstudenta = idStudent;

            sredniaStudenta := avg(wszystkieOceny);

            if sredniaStudenta < srednia
            then
                delete from student where idstudenta = idStudent;
                delete from ocena where idstudenta = idStudent;
            end if
        end if
    end loop;
    close Cur_zad1;
end;