ocp题库怎么背：11g-051-V9.02-第178题
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ocp题库怎么背：11g-051-V9.02-第178题，完整题库请点击这里联系老师咨询了解
178.Evaluate these two SQL statements:
SELECT last_name, salary, hire_date FROM EMPLOYEES ORDER BY salary DESC;
SELECT last_name, salary, hire_date FROM EMPLOYEES ORDER BY 2 DESC;
What is true about them?
A. The two statements produce identical results.
B. The second statement returns a syntax error.
C. There is no need to specify DESC because the results are sorted in descending order by default.
D. The two statements can be made to produce identical results by adding a column alias for the salary column in the second SQL statement.
Answer: A
试题解析：
order by 2意思是select语句中第二个排序，即为salary，即排序是一样的。
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