【单选题】显示出表employees的全部列,各个列中间用逗号连接,列头显示成OUT_PUT。以下对应查询代码正确的是().
A.
SELECT CONCAT(`employee_id`,`first_name`,`last_name`,`email`,`phone_number`,`job_id`,`salary`,IFNULL(commission_pct,0),`manager_id`,`department_id`,`hiredate`) AS OUT_PUT FROM employees;
B.
SELECT CONCAT(`employee_id`,',',`first_name`,',',`last_name`,',',`email`,',',`phone_number`,',',`job_id`,',',`salary`,',',IFNULL(commission_pct,0),',',`manager_id`,',',`department_id`,',',`hiredate`) AS OUT_PUT FROM employees;
C.
SELECT CONCAT(`employee_id`,',',`first_name`,',',`last_name`,',',`email`,',',`phone_number`,',',`job_id`,',',`salary`,',',commission_pct,',',`manager_id`,',',`department_id`,',',`hiredate`) AS OUT_PUT FROM employees;
D.
SELECT CONCAT(`employee_id`,`first_name`,`last_name`,`email`,`phone_number`,`job_id`,`salary`,commission_pct,`manager_id`,`department_id`,`hiredate`) AS OUT_PUT FROM employees;