SN CHAR(30), SA INT, SD CHAR(20) }； (2)CREATE TABLE C( CNo INT PRIMARY KEY, CN CHAR(20), TN CHAR(20) }； (3)CREATE TABLE SC SNo INT, CNo INT, G INT, PRIMARY KEY(SNo,CNo), FOREIGN KEY(SNo)REFERENCES S(SNo), FOREIGN KEY(CNo)REFERENCES C(CNo) }; 三、（每小题6分，共18分】 (I)GRANT SELECT,INSERT(SNo,CNo)ON SC TO王小兰； (2)DELETE FROM SC WHERE SNo IN (SELECT SNo FROM S WHERE SN='李小冬' )； (3)SELECT CNo,AVG(G) FROM SC,C WHERE SC.CNo=C.CNo AND TN LIKE% GROUP BY CNo; 437SN CHAR(30) , SA INT, SD CHAR(20) (2)CREATE TABLE C{ CNo INT PRI岛1ARY KEY , CN CHAR(20) , TN CHAR(20) (3)CREATE TABLE SCI SNo INT, CNo INT, G INT, PRIMARY KEY(SNo ,CNo) , FOREIGN KEY(SNo) REFERENCES S(SNo) , FOREIGN KEY(CNo) REFERENCES C(CNo) 三、(每小题 (l)GRANT SELECT,INSERT(SNo,CNo) ON SC TO 兰z (2)DELETE FROM SC WHERE SNo IN (SELECT SNo FROMS WHERE SN=' ) ; (3)SELECT CNo ,AVG(G) FROM SC,C WHERE SC. CNo=C. CNo AND TN LIKE' GROUP BY CNo; 437