SET serveroutput ON;
CREATE OR REPLACE PROCEDURE perc_objednavok (hladany_dodavatel IN VARCHAR2)
IS
    CURSOR dodobj IS SELECT * FROM OBJEDNAVKY INNER JOIN DODAVATELIA ON OBJEDNAVKY.ID_DOD = DODAVATELIA.ID_DOD;
    obj dodobj%ROWTYPE;
    pocet NUMBER;
    celkom NUMBER;
BEGIN
    pocet := 1;
    celkom := 0;
    OPEN dodobj;
    LOOP
        FETCH dodobj INTO obj;
        IF (obj.ID_DOD > 0)THEN-- hladany_dodavatel) THEN potom dorobic
            pocet := pocet + 1;
        END IF;
        celkom := celkom +1;
    END LOOP;
    dbms_output.put_line('Percentualny podiel objednaavok od dodavatela '|| hladany_dodavatel ||' je ' || pocet/celkom*100 || '%');

EXCEPTION
    WHEN NO_DATA_FOUND THEN --ak zadame neexistujuceho dodavatela
        dbms_output.put_line('CHYBA: Prazdna tabulka');
    WHEN OTHERS THEN
        Raise_Application_Error (-20206, 'CHYBA');
END;
/
SHOW ERRORS;

EXEC PERC_OBJEDNAVOK;
SHOW ERRORS;