39.choose the best answer
View the Exhibit and examine the description of the EMPLOYEES table.
You want to calculate the total remuneration for each employee. Total remuneration is the sum of the annual salary and the percentage commission earned for a year.
Only a few employees earn commission.
Which SQL statement would you execute to get the desired output?
A) SELECT first_name, salary, salary*12 + NVL(salary, 0)*commission_pct "Total"
FROM EMPLOYEES;
B) SELECT first_name, salary, salary*12+(salary*NVL2(commission_pct,
salary,salary+commission_pct)) "Total"
FROM EMPLOYEES;
C) SELECT first_name, salary, (salary + NVL(commission_pct,0)*salary)*12 "Total"
FROM EMPLOYEES;
D) SELECT first_name, salary, salary*12+salary*commission_pct "Total"
FROM EMPLOYEES;
Answer：A
(解析：题眼是“Only a few employees earn commission”，说明有人的佣金是 null，所以要用 nvl 函数)