-------------------1------------
ALTER TABLE KLIENCI
    ADD TELEFON NUMBER(9);
-----------2----------------
ALTER TABLE KLIENCI
    DROP (NR_DOWODU);
---------------3------------------
ALTER TABLE SAMOCHODY RENAME COLUMN MODEL TO MODEL_SAMOCHODU;
----------------4---------------------
ALTER TABLE NAPRAWA
    MODIFY(CENA CHECK(1<CENA AND CENA <1000));
----------------5----------------
INSERT INTO MAGAZYN VALUES(12, 'MAJONEZ', 21, 5);
----------------6---------------
----------------7------------------
COMMENT ON COLUMN KLIENCI.MIEJSCOWOSC IS 'ZOSTAWIAM TO BEZ KOMENTARZA ;)';
  SELECT COLUMN_NAME, COMMENTS FROM USER_COL_COMMENTS WHERE  TABLE_NAME LIKE 'KLIENCI';
----------------8-------------
SELECT * FROM USER_CONS_COLUMNS WHERE TABLE_NAME='SAMOCHODY';
----------------9-------------
--------------10---------------
---------------11-------------
SELECT S.MARKA, S.MODEL FROM SAMOCHODY S
WHERE S.KRAJ_PROD IN (SELECT S.KRAJ_PROD FROM SAMOCHODY S
GROUP BY S.KRAJ_PROD HAVING COUNT(S.ID_SAM) = (SELECT MIN(COUNT(S.ID_SAM))
FROM SAMOCHODY S GROUP BY S.KRAJ_PROD));
---------------12------------
SELECT S.ID_SAM,SUM(M.CENA) FROM SAMOCHODY S,NAPRAWA N, CZ_NAPRAW CN, MAGAZYN M
WHERE S.ID_SAM = N.ID_SAM AND CN.ID_NAP = N.ID_NAP AND M.ID_CZESCI = CN.ID_CZESCI AND S.NR_REJ LIKE 'KR%'
GROUP BY S.ID_SAM
HAVING SUM(M.CENA) > ( SELECT SUM(CENA) FROM MAGAZYN);
------------------13------------
SELECT MIASTO FROM (SELECT K.MIEJSCOWOSC AS MIASTO, COUNT(N.ID_NAP) AS NAPRAWY FROM KLIENCI K, NAPRAWA N
WHERE  K.ID_KLI = N.ID_KLI
GROUP BY K.MIEJSCOWOSC
HAVING COUNT(N.ID_NAP) = (SELECT MIN(NAPRAWY) FROM (SELECT K.MIEJSCOWOSC AS MIASTO,COUNT(N.ID_NAP) AS NAPRAWY FROM KLIENCI K, NAPRAWA N
 WHERE K.ID_KLI = N.ID_KLI
 GROUP BY K.MIEJSCOWOSC)));