标签:category promotions REMARK 12c 071 19 TV promo cost
19.choose the best answer
View the Exhibit and examine the structure of the PROMOTIONS table.
Evaluate the following SQL statement:
SQL>SELECT promo_name,CASE
WHEN promo_cost>=(SELECT AVG(promo_cost)
FROM promotions
WHERE promo_category= 'TV')
THEN 'HIGH'
ELSE 'LOW'
END COST_REMARK
FROM promotions;
Which statement is true regarding the outcome of the above query?
A) It shows COST_REMARK for all the promos in the promo category 'TV' .
B) It produces an error because subqueries cannot be used with the CASE expression.
C) It shows COST_REMARK for all the promos in the table.
D) It produces an error because the subquery gives an error.
Answer:C
(解析:category 'TV'只是判定 promo_cost 的一个条件,显示的是所有 category 的内容。
使用如下语句验证:
SELECT promo_name,promo_category,CASE
WHEN promo_cost>=(SELECT AVG(promo_cost)
FROM promotions
WHERE promo_category= 'TV')
THEN 'HIGH'
ELSE 'LOW'
END COST_REMARK
FROM promotions
where rownum < 30;
)
标签:category,promotions,REMARK,12c,071,19,TV,promo,cost 来源: https://blog.51cto.com/13854012/2355045
本站声明: 1. iCode9 技术分享网(下文简称本站)提供的所有内容,仅供技术学习、探讨和分享; 2. 关于本站的所有留言、评论、转载及引用,纯属内容发起人的个人观点,与本站观点和立场无关; 3. 关于本站的所有言论和文字,纯属内容发起人的个人观点,与本站观点和立场无关; 4. 本站文章均是网友提供,不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属;如您发现该文章侵犯了您的权益,可联系我们第一时间进行删除; 5. 本站为非盈利性的个人网站,所有内容不会用来进行牟利,也不会利用任何形式的广告来间接获益,纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。