现有关系模式: EMP(empno,ename,mgr,sal,workday) 以及DEPT(deptno,dname,loc) ,以下视图中不可能更新的为________
举一反三
- 智慧职教: 表结构如下：dept（deptno,dname）,emp(empno,ename,job,hiredate,sal，deptno)。创建视图查询系部名称、教师姓名，职位，工资信息。
- 查询部门20的员工数量,每个月的工资总和及平均工资( ) A: SELECT sum(nvl(sal,0)),avg(nvl(sal,0)) from emp B: SELECT ename,sum(nvl(sal,0)),avg(nvl(sal,0)) from emp where deptno =20 group by deptno C: SELECT ename,count(empno),sum(nvl(sal,0)),avg(nvl(sal,0)) from emp where deptno =20 group by deptno D: SELECT count(empno),sum(nvl(sal,0)),avg(nvl(sal,0)) from emp where deptno =20 group by deptno
- 以下语句不正确的是( ) A: select * from emp B: select ename,hiredate,sal from emp C: select * from emp order deptno D: select * from where deptno=1 and sal<300
- 以下语句不正确的是( ) A: select * from emp; B: select ename,hiredate,sal from emp; C: select * from emp order deptno; D: select * from where deptno=1
- 列出所有员工的姓名、部门名称和工资。正确的SQL语句有________。 A: SELECT a.ename <br> ,(SELECT b.dname FROM dept b) AS dname <br> ,sal <br>FROM emp a B: SELECT a.ename <br> ,(SELECT b.dname FROM dept b WHERE b.deptno=a.deptno) AS dname <br> ,sal <br>FROM emp a; C: SELECT a.ename,b.dname,sal <br>FROM emp a,dept D: SELECT a.ename,b.dname,sal <br>FROM emp a,dept b <br>WHERE a.deptno=b.deptno