... LA '3THG', '6THG' , '9THG', '1NAM', '2NAM', '3NAM'ALTER TABLE HANGHOA ADD CONSTRAINT CK_BAOHANH CHECK(BAOHANH IN ('3THG','6THG' ... ('H001', 'DVD TIEN DAT', 1200000, 22, '6THG', 'DIEN TU TIEN DAT', 'KHONG')INSERT INTO HANGHOA VALUES ('H002', 'VCD TIEN DAT', ... ('H005', 'CD SONY', 1000000, 2, '12THG', 'DIEN TU TIEN DAT', 'KHONG') INSERT INTO KHACHHANG VALUES ('KH001', 'ERIC CANTONA',...