问题 填空题

对于图书管理数据库,查询每类图书的册数和平均单价。请对下面的SQL语句填空:
SELECT分类号, 【12】 FROM 图书;
【13】 分类号

答案

参考答案:【12】COUNT(*),AVG(单价)
【13】GROUP BY

解析:[知识点] 分组与计算查询
[评析] 查询操作用SELECT命令实现,本题是查询结果出自一个表的分组计算查询,按图书的分类号进行分组,通过"GROUP BY分类号"实现。计算每项类图书的平均单价通过AVG(单价)实现,COUNT(*)函数用于统计每类图书的册数。

多项选择题 案例分析题
阅读理解

A beautiful woman took a plane on business. She found her seat and sat down next to a young man. The man was just thinking of making a few dollars on the plane. When he saw the woman, he got an idea.

“Hey! Would you like to play a game?” he asked the woman. “No, thank you. I just want to take a nap (打盹),” the woman answered. “It’s really easy. All you have to do is to answer the questions that I ask you. If you don’t know the answer, you give me five dollars. If I don’t know the answer to your question, then I’ll give you five dollars.” “No,” the woman still refused. “OK. If I don’t know the answer to your question, I’ll give you five hundred dollars. How about that?” the man said. Then the woman became interested and decided to join in the game.

“OK. How many moons does Jupiter (木星) have?” asked the young man. The woman reached into her purse and took out a five-dollar bill. “What goes up the mountain with three legs and comes back with four?” the woman asked. Then the young man took out his computer and searched the Internet for an answer. Minutes later, the young man handed five hundred dollars to the woman.

After a few hours, the young man really wanted to know the answer to the question. So he asked the woman, “What is the answer to your question?” The woman reached into her purse and handed the young man a five-dollar bill.

小题1:Why did the man ask the woman to play a game?

A.He wanted to show his kindness.

B.He wanted to have a pleasant journey.

C.He wanted to earn some money from it.

D.He wanted to make friends with the woman.小题2:How much did the woman get at the end of the story?

A.$ 500.

B.$ 5.

C.$ 10.

D.$ 490.小题3:What can we learn from the last paragraph?

A.The woman told the man the answer to her question.

B.The woman gave the man’s money back to him.

C.The woman asked the man another question.

D.The woman didn’t know the answer, either.小题4:We can learn from the story that the woman is ______.

A.clever

B.friendly

C.polite

D.honest