问题 单项选择题

下列各题使用如下表的数据:

部门表

部门号 部门名称
40 家用电器部
10 电视录摄像机部
20 电话手机部
30 计算机部

商品表

部 门 号 商 品 号 商品名称 单 价 数 量 产 地
40 0101 A牌电风扇 200.00 10 广东
40 0104 A牌微波炉 350.00 10 广东
40 0105 B牌微波炉 600.00 10 广东
20 1032 C牌传真机 1000.00 20 上海
40 0107 D牌微波炉A 420.00 10 北京
20 0110 A牌电话机 200.00 50 广东
20 0112 B牌手机 2000.00 10 广东
40 0202 A牌电冰箱 3000.00 2 广东
30 1041 B牌计算机 6000.00 10 广东
30 0204 C牌计算机 10000.00 10 上海

SQL语句
SELECT产地,COUNT(*)
FROM商品表
WHERE单价>200
GROUP BY产地HAVING COUNT(*)>=2
ORDER BY 2 DESC
查询结果的第一条记录的产地和提供的商品种类数是( )。

A.北京,1

B.上海,2

C.广东,5

D.广东,7

答案

参考答案:C

解析: 本题考查了SQL语句的功能。ORDER BY短语可以对查询结果排序(DESC降序排列),GROUP BY短语用来分组记录,HAVING语句在GROUP BY短语后对结果进行筛选。本题SQL语句的作用是,在商品表中查询那些提供的商品单价大于200元,并且提供两种以上商品的地方,并按提供的商品种类数降序排列。

单项选择题
单项选择题

For many people today, reading is no longer relaxation. To keep up their work they must read letters, reports, trade publications, interoffice communications, not to mention newspapers and magazines: a never ending flood of words. In (1) a job or advancing in one, the ability to read and comprehend (2) can mean the difference between success and failure. Yet the unfortunate fact is that most of us are (3) readers. Most of us develop poor reading (4) at an early age, and never get over them. The main deficiency (5) in the actual stuff of language itself—words. Taken individually, words have (6) meaning until they are strung together into phrases, sentences and paragraphs. (7) , however, the untrained reader does not read groups of words. He laboriously reads one word at a time, often regressing to (8) words or passages. Regression, the tendency to look back over (9) you have just read, is a common bad habit in reading. Another habit which (10) down the speed of reading is vocalization—sounding each word either orally or mentally as (11) reads.
To overcome these bad habits, some reading clinics use a device called an (12) , which moves a bar(or curtain) down the page at a predetermined speed. The bar is set at a slightly faster rate (13) the reader finds comfortable, in order to "stretch" him. The accelerator forces the reader to read fast, (14) word by word reading, regression and subvocalization practically impossible. At first (15) is sacrificed for speed. But when you learn to read ideas and concepts, you will not only read faster, (16) your comprehension will improve. Many people have found (17) reading skill drastically improved after some training. (18) Charlie Au, a business manager, for instance. His reading rate was a reasonably good 172words a minute (19) the training; now it is an excellent 1,378 words a minute. He is delighted that how he can (20) a lot more reading material in a short period of time.

A.but
B.nor
C.or
D.for