当你执行以下查询语句：SELECT employeesno，ename FROM employees WHERE emp

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;

You need to create a view EMP_VU. The view should allow the users to manipulate the records of only the employees that are working for departments 10 or 20. Which SQL statement would you use to create the view EMP_VU? （）

A. CREATE VIEW emp_vu AS SELECT * FROM employees WHERE department _ id IN (10,20);

B. CREATE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) WITH READ ONLY;

C. CREATE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) WITH CHECK OPTION;

D. CREATE FORCE VIEW emp_vu AS SELECT * FROM employees WITH department_id IN (10,20);

E. CREATE FORCE VIEW emp_vu AS SELECT * FROM employees WHERE department_id IN (10,20) NO UPDATE;

A.IN

B.BETWEEN……and

C.LIKE

D.<=

对于第7题的两个基本表，有一个SQL语句： SELECT ENO, ENAME FROM EMP WHERE DNO NOT IN (SELECT DNO FROM DEPT WHERE DNAME='金工车间');其等价的关系代数表达式是：______。

A．πENO,ENAME(σDNAME≠'金工车间'(EMPDEPT))

B．πENO,ENAME

C．πENO,ENAME(EMP)-πENO,ENAME (σDNAME='金工车间'(EMPDEPT))

D．πENO,ENAME (EMP)-πENO,ENAME (σDNAME≠'金工车间'(EMPDEPT))

Examine the following commands and their output:SQL> SELECT ename, sal FROM emp WHERE ename=‘JAMES‘; ENAME SAL JAMES 1050QL> UPDATE emp SET sal=sal+sal*1.2 WHERE ename=‘JAMES‘;1 row updated.SQL> SELECT ename, sal FROM emp WHERE ename=‘JAMES‘; ENAME SAL JAMES 2310View the exhibit and examine the Flashback Version Query that was executed after the preceding commands.What could be the possible cause for the query not displaying any row?（）

A. Flashback logging is not enabled for the database.

B. The changes made to the table are not committed.

C. Supplemental logging is not enabled for the database.

D. The database is not configured in ARCHIVELOG mode.

The EMP table has these columns:ENAME VARCHAR2(35)SALARY NUMBER(8,2)HIRE_DATE DATEManagement wants a list of names of employees who have been with the company for more than five years. Which SQL statement displays the required results? （）

A. SELECT ENAME FROM EMP WHERE SYSDATE-HIRE_DATE >5;

B. SELECT ENAME FROM EMP WHERE HIRE_DATE-SYSDATE >5;

C. SELECT ENAME FROM EMP WHERE (SYSDATE_HIRE_DATE)/365 >5;

D. SELECT ENAME FROM EMP WHERE (SYSDATE_HIRE_DATE)*/365 >5;

A.select employeesno，ename Name，job from employees where ename=‘SMITH’

B.select employeesno，ename ‘Name’，job from employees where ename=SMITH

C.select employeesno，ename “Name”，job from employees where ename=‘SMITH’

D.select employeesno，ename ‘Name’，job frome mployees wheree name=‘SMITH’

A. 这个语句是符合语法的

B. 这个语句是不能执行的,因为缺少HAVING子句

C. 这个语句是不能执行的,因为分组的条件列不在SELECT列表中

D. 这个语句是不能执行的,因为GROUP BY子句应该在主查询中,而不是在子查询中

E. 在主查询的WHERE条件中,不应该用IN,而应该用等号