【OCP-12c】CUUG最新考试原题整理及答案（071-9）

最新推荐文章于 2021-04-09 18:54:40 发布

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最新推荐文章于 2021-04-09 18:54:40 发布

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原文链接：http://www.cnblogs.com/cnblogs5359/p/10382576.html

本文详细解析了SQL中分组函数的正确使用方法，通过一个具体的例子展示了如何使用GROUP BY子句来配合分组函数，以实现对数据的正确汇总。强调了分组函数中未出现在GROUP BY子句中的列必须出现在分组函数中的规则。

9、（5-5） choose the best answer
View the Exhibit and examine the structure of the SALES and STORES tables.
You want to display the store name and the total quantity sold for each item in the store.

Which SQL statement will give the required output?
A) SELECT str.name, s1.items_id, SUM(s1.quantity)
FROM sales s1 JOIN stores str
ON (s1.store_id = str.store_id)
GROUP BY str.name, s1.items_id, s1.quantity;

B) SELECT str.name, s1.items_id, SUM(s1.quantity)
FROM sales s1 JOIN stores str
ON (s1.store_id = str.store_id)
GROUP BY str.name, s1.items_id;

C) SELECT str.name, s1.items_id,
(SELECT SUM(quantitY)
FROM sales sls
ON sls.store_id = s1.store_id
GROUP BY sls.store_id)
FROM sales s1 JOIN stores str
ON (s1.store_id = str.store_id);

D) SELECT str.name, s1.items_id, SUM(s1.quantity)
FROM sales s1 JOIN stores str ON (s1.store id = str.store_id)
GROUP BY s1.items_id, s1.quantity;

Answer：B
(解析：分组函数的最基本特点，没有出现在分组函数中的列必须要出现在 group by 子句中。)

转载于:https://www.cnblogs.com/cnblogs5359/p/10382576.html