Choose the best answer
The EMPLOYEES table contains columns EMP_ID of data type NUMBER and HIRE_DATE of data type DATE
You want to display the date of the first Monday after the completion of six months since hiring
The NLS_TERRITORY parameter is set to AMERICA in the session and, therefore, Sunday is the first day ofthe week
Which query can be used?
A) SELECT emp_id,NEXT_DAY(ADD_MONTHS(hite_date,6), 'MONDAY') FROM employees;
B) SELECT emp_id,ADD_MONTHS(hire_date,6), NEXT_DAY('MONDAY') FROM employees;
C) SELECT emp_id,NEXT_DAY(MONTHS_BETWEEN(hire_date,SYSDATE),6) FROM employees;
D) SELECT emp_id,NEXT_DAY(ADD_MONTHS(hire_date,6),1) FROM employees;
Answer:A
（解析：本题 A 和 D 的答案非常相似，但是因为周日是第一天，所以 D 答案显示的是周日的日期。
在使用 next_day 的时候，要注意字符集，如果是中文的，就不能用 monday，而是用星期一：
SELECT NEXT_DAY(ADD_MONTHS(hiredate,6), '星期一') from emp2;