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单选题
在Oracle中，下面哪条语句当COMM字段为空时显示0，不为空时显示COMM的值（）。
A
select ename,nvl（comm.,0）from emp
B
select ename,null（comm.,0）from emp
C
SELECT ename,NULLIF（comm,0）FROM emp
D
SELECT ename,DECODE（comm.,NULL,0）FROM emp
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客户需要计算EMP表中所有职工12*salary* commission_pct的值.EMP表结构如下：LAST NAME VARCNAR2（35）NOT NULL SALARY NUMBER（9，2）NOT NULL COMMISION_PCTNUMBER（4，2）哪个语句可以查询计算EMP表中所有职工行？（）A、SELECT last_name，12*salary* commission_pct FROM empB、SELECT last_name，12*salary*（commission_pct，0）FROM empC、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
考题
单选题EMPLOYEES中职员编号为90的职员的commission_pct为空值，salary为1000，语句select12*salary*（commission_pct+0.2）comm from EMPLOYEES；comm显示的结果是（）。A
12000B
0C
2400D
NULL
考题
单选题Evaluate this SQL statement: SELECT ename, sal, 12*sal+100 FROM emp; The SAL column stores the monthly salary of the employee. Which change must be made to the above syntax to calculate the annual compensation as "monthly salary plus a monthly bonus of $100, multiplied by 12"?（）A
No change is required to achieve the desired results.B
SELECT ename, sal, 12*(sal+100) FROM emp;C
SELECT ename, sal, (12*sal)+100 FROM emp;D
SELECT ename, sal+100,*12 FROM emp;
考题
单选题查询出EMP表中COMM字段为空的记录（）A
select * from emp where comm='';B
select * from emp where comm=null;C
select * from emp where nvl(comm)=0;D
select * from emp where comm is null;E
select * from emp where nvl(comm,0)=0;
考题
单选题在Oracle中，下面哪条语句当COMM字段为空时显示0，不为空时显示COMM的值（）。A
select ename,nvl（comm.,0）from empB
select ename,null（comm.,0）from empC
SELECT ename,NULLIF（comm,0）FROM empD
SELECT ename,DECODE（comm.,NULL,0）FROM emp
考题
( 难度：中等)以下哪些Mysql语句是正确的？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;E.select * from where deptno=1 group by sal;
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