OCP 1Z0 051 66

66. View the Exhibit and examine the data in the COSTS table. 
You need to generate a report that displays the IDs of all products in the COSTS table whose unit price is 
at least 25% more than the unit cost. The details should be displayed in the descending order of 25% of 
the unit cost. 
You issue the following query: 
SQL>SELECT prod_id 
FROM costs 
WHERE unit_price >= unit_cost * 1.25 
ORDER BY unit_cost * 0.25 DESC; 
Which statement is true regarding the above query? 


A. It executes and produces the required result. 
B. It produces an error because an expression cannot be used in the ORDER BY clause. 
C. It produces an error because the DESC option cannot be used with an expression in the ORDER BY 
clause. 
D. It produces an error because the expression in the ORDER BY clause should also be specified in the 

SELECT clause. 

ORDER BY 后可以跟 列名、别名、表达式、列位置（数字）

SQL> SELECT prod_id  2    FROM sh.costs  3   WHERE unit_price >= unit_cost * 1.25  4     AND rownum <= 5  5   ORDER BY unit_cost * 0.25 DESC;   PROD_ID----------        17        14        14        14        145 rows selected

Answer: A