如有不当之处还请多多指教...
本人劳动成果，还请转载署名出处。。。
ORACLE实验二(二)
CT DISTINCT MAKER,MAX(PRICE)
FROM PRODUCT ,PC
WHERE PRODUCT.MODEL=PC.MODEL AND TYPE='PC'
GROUP BY MAKER;
SELECT DISTINCT MAKER,COUNT(*) FROM PRODUCT
WHERE TYPE='PC'
GROUP BY MAKER
HAVING COUNT(*)>=3;
UPDATE PRODUCT
SET MAKER='B'
WHERE MAKER='A';
DELETE PRODUCT P1
WHERE P1.TYPE='LAPTOP' AND EXISTS
(
SELECT * FROM PRODUCT P2
WHERE P2.TYPE='Printer'
AND P1.MODEL=P2.MODEL
);
ROLLBACK;