OCP 1Z0 051 17
17. View the E xhibit and examine the data in the EMPLOYEES table.
You want to generate a report showing the total compensation paid to each employee to date.
You issue the following query:
SQL>SELECT ename ' joined on ' hiredate
', the total compensation paid is '
TO_CHAR(ROUND(ROUND(SYSDATE-hiredate)/365) * sal + comm)
"COMPENSATION UNTIL DATE"
FROM employees;
What is the outcome?
A. It generates an error because the alias is not valid.
B. It executes successfully and gives the correct output.
C. It executes successfully but does not give the correct output.
D. It generates an error because the usage of the ROUND function in the expression is not valid.
E. It generates an error because the concatenation operator can be used to combine only two items.
考点：null
null与任何值四则运算结果均为空值
我们以emp表为例显示该题结果
Answer: C
You want to generate a report showing the total compensation paid to each employee to date.
You issue the following query:
SQL>SELECT ename ' joined on ' hiredate
', the total compensation paid is '
TO_CHAR(ROUND(ROUND(SYSDATE-hiredate)/365) * sal + comm)
"COMPENSATION UNTIL DATE"
FROM employees;
What is the outcome?
A. It generates an error because the alias is not valid.
B. It executes successfully and gives the correct output.
C. It executes successfully but does not give the correct output.
D. It generates an error because the usage of the ROUND function in the expression is not valid.
E. It generates an error because the concatenation operator can be used to combine only two items.
考点：null
null与任何值四则运算结果均为空值
SQL> select 1 + null as c2,2 as c3 from dual;
C2 C3
---------- ----------
2
Executed in 0.016 seconds
在oracle中，字符串与null连接不为空
SQL> select '有值' || null as "不为空" from dual; 不为空 ------ 有值 Executed in 0.016 seconds
我们以emp表为例显示该题结果
SQL> select * from emp;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- ---------- ---------- ----------- ---------- ---------- ----------
7369 SMITH CLERK 7902 1980-12-17 800 20
7499 ALLEN SALESMAN 7698 1981-2-20 1600 300 30
7521 WARD SALESMAN 7698 1981-2-22 1250 500 30
7566 JONES MANAGER 7839 1981-4-2 2975 20
7654 MARTIN SALESMAN 7698 1981-9-28 1250 1400 30
7698 BLAKE MANAGER 7839 1981-5-1 2850 30
7782 CLARK MANAGER 7839 1981-6-9 2450 10
7788 SCOTT ANALYST 7566 1982-12-9 3000 20
7839 KING PRESIDENT 1981-11-17 5000 10
7844 TURNER SALESMAN 7698 1981-9-8 1500 0 30
7876 ADAMS CLERK 7788 1983-1-12 1100 20
7900 JAMES CLERK 7698 1981-12-3 950 30
7902 FORD ANALYST 7566 1981-12-3 3000 20
7934 MILLER CLERK 7782 1982-1-23 1300 10
14 rows selected
Executed in 0.032 seconds
SQL>
SQL> SELECT ename || ' joined on ' || hiredate ||
2 ', the total compensation paid is ' ||
3 to_char(round(round(SYSDATE - hiredate) / 365) * sal + comm) "COMPENSATION UNTIL DATE"
4 FROM emp;
COMPENSATION UNTIL DATE
--------------------------------------------------------------------------------
SMITH joined on 17-12月-80, the total compensation paid is
ALLEN joined on 20-2月 -81, the total compensation paid is 53100
WARD joined on 22-2月 -81, the total compensation paid is 41750
JONES joined on 02-4月 -81, the total compensation paid is
MARTIN joined on 28-9月 -81, the total compensation paid is 42650
BLAKE joined on 01-5月 -81, the total compensation paid is
CLARK joined on 09-6月 -81, the total compensation paid is
SCOTT joined on 09-12月-82, the total compensation paid is
KING joined on 17-11月-81, the total compensation paid is
TURNER joined on 08-9月 -81, the total compensation paid is 49500
ADAMS joined on 12-1月 -83, the total compensation paid is
JAMES joined on 03-12月-81, the total compensation paid is
FORD joined on 03-12月-81, the total compensation paid is
MILLER joined on 23-1月 -82, the total compensation paid is
14 rows selected
Executed in 0.078 seconds
Answer: C