select ename,nvl(comm.,0)from emp
select ename,null(comm.,0)from emp
SELECT ename,NULLIF(comm,0)FROM emp
SELECT ename,DECODE(comm.,NULL,0)FROM emp
第1题:
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’
第2题:
若在教师表中查找还没有输入工龄的记录,使用的SQL语句为
A.SELECT * FROM 教师 WHERE 工龄IS NOT NULL
B.SELECT * FROM 教师 WHERE 工龄=0
C.SELECT * FROM 教师 WHERE 工龄 IS NULL
D.SELECT * FROM 教师 WHERE 工龄=NULL
第3题:
A.SELECT last_name,12*salary* commission_pct FROM emp
B.SELECT last_name,12*salary*(commission_pct,0)FROM emp
C.SELECT last_name,12*salary*(nvl(commission_pct,0))FROM emp如果oracle第一个参数为空那么显示第二个参数的值,如果第一个参数的值不为空,则显示第一个参数本来的值
D.SELECT last_name,12*salary*(decode(commission_pct,0))FROM emp
第4题:
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))
第5题:
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;
第6题:
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;
第7题:
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.
第8题:
A.12000
B.0
C.2400
D.NULL
第9题:
设选课表的结构为:(学号、课程号、成绩),其中学号+课程号为主键。若要找出成绩不为空的记录,应当使用的SELECT语句是______。
A.SELECT*FROM选课表WHERE成绩IS""
B.SELECT*FROM选课表WHERE成绩=0
C.SELECT*FROM选课表WHERE成绩<>NULL
D.SELECT*FROM选课表WHERE成绩ISNOT NULL
第10题:
A.SELECT TOP 5 * FROM EMP
B.SELECT DISTINCT 5 * FROM EMP
C.SELECT * FROM EMP WHERE ROWNUM<6
D.SELECT * FROM EMP WHERE ROWNUM=5