单项选择题

Examine the data of the EMPLOYEES table.
EMPLOYEES (EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID)

Evaluate this SQL statement:

What is its output?（）

A.
B.
C.
D.
E. The SQL statement produces an error.

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单项选择题

Which SELECT statement should you use to extract the year from the system date and display it in the format "1998"?（）

A. SELECT TO_CHAR(SYSDATE,'yyyy') FROM dual;
B. SELECT TO_DATE(SYSDATE,'yyyy') FROM dual;
C. SELECT DECODE(SUBSTR(SYSDATE, 8), 'YYYY') FROM dual;
D. SELECT DECODE(SUBSTR(SYSDATE, 8), 'year') FROM dual;
E. SELECT TO_CHAR(SUBSTR(SYSDATE, 8,2),'yyyy') FROM dual;

单项选择题

The EMPLOYEES table contains these columns:
LAST_NAME VARCHAR2 (25)
SALARY NUMBER (6,2)
COMMISSION_PCT NUMBER (6)
You need to write a query that will produce these results:
1. Display the salary multiplied by the commission_pct.
2. Exclude employees with a zero commission_pct.
3. Display a zero for employees with a null commission value.
Evaluate the SQL statement:
SELECT LAST_NAME, SALARY*COMMISSION_PCT
FROM EMPLOYEES
WHERE COMMISSION_PCT IS NOT NULL;
What does the statement provide?（）

A.All of the desired results
B.Two of the desired results
C.One of the desired results
D.An error statement

单项选择题

A subquery can be used to （）.

A. Create groups of data
B. Sort data in a specific order
C. Convert data to a different format
D. Retrieve data based on an unknown condition

Examine the data of the EMPLOYEES table. EMPLOYEES (EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID) Evaluate this SQL statement: What is its output?（）

相关考题

Examine the data of the EMPLOYEES table.
EMPLOYEES (EMPLOYEE_ID is the primary key. MGR_ID is the ID of managers and refers to the EMPLOYEE_ID)

Evaluate this SQL statement:

What is its output?（）