10. View the Exhibit and examine the structure of the PROMOTIONS table.
Each promotion has a duration of at least seven days .
Your manager has asked you to generate a report, which provides the weekly cost for each promotion
done to l date.
Which query would achieve the required result?
A. SELECT promo_name, promo_cost/promo_end_date-promo_begin_date/7
FROM promotions;
B. SELECT promo_name,(promo_cost/promo_end_date-promo_begin_date)/7
FROM promotions;
C. SELECT promo_name, promo_cost/(promo_end_date-promo_begin_date/7)
FROM promotions;
D. SELECT promo_name, promo_cost/((promo_end_date-promo_begin_date)/7)
FROM promotions;
Answer: D
題目解析:
題目的意思:是求每個促銷在促銷期間內,每周的的平均消費。
由給出的表可知:促銷的總花費為 promo_cost 促銷的時間長度為 (promo_end_date-promo_begin_date),把促銷時間長度轉換為周需要除7為
(promo_end_date-promo_begin_date)/7,所以每周的平均花費為promo_cost/( (promo_end_date-promo_begin_date)/7)
顯然D是正確的,這題主要考察運算式的運算順序,答案ABC在執行的時候都會提示法錯誤。