create or replace function f3(datum in date) return number as

check_this_date date := datum;
NAME_des_BUCHES varchar2(255) := '';
num_bernd number := 0;

cursor c1 is SELECT COUNT(*) count_youre_books, KUNDE.AUSWEISNR, kunde.Vorname, AUSLEIHE.barcode_id, AUSLEIHE.ENTLEIHENDE from kunde, ausleihe where AUSLEIHE.ENTLEIHENDE < check_this_date group by AUSLEIHE.barcode_id;
    
c2 c1%rowtype;

begin
OPEN c1;
loop

    fetch c1 into c2;
    exit when c1%notfound;
    
    num_bernd := c2.count_youre_books;
    EXECUTE IMMEDIATE 'SELECT BUCH.TITEL from buch, buch_kopien WHERE buch_kopien.barcode_id = ' || c2.barcode_id || ' AND buch.isbn = buch_kopien.isbn' into NAME_des_BUCHES;
    
    dbms_output.put_line('K_ID: ' || c2.AUSWEISNR || ', Vorname: ' || c2.vorname || ', Buch: ' || NAME_des_BUCHES);
    
end loop;
CLOSE c1;
end;

declare
datum date := sysdate;
zahl number := 0;
begin
zahl := f3(datum);
end;