单项选择题
以下说法错误的是( ) A.SELECT max(sal),deptno,job FROM EMP group by sal; B.SELECT max(sal),deptno,job FROM EMP group by deptno; C.SELECT max(sal),deptno,job FROM EMP; D.SELECT max(sal),deptno,job FROM EMP group by job;
单项选择题 以下删除表正确的( ) A.Delete * from emp B.Drop database emp C.Drop * from emp D.delete database emp
单项选择题 以下哪种操作能够实现实体完整性( ) A.设置唯一键 B.设置外键 C.减少数据冗余 D.设置主键
单项选择题 以下哪项用来排序( ) A.ORDERED BY B.ORDER BY C.GROUP BY D.GROUPED BY