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[单选题]

假设S(S#，SN，SEX，AGE，DEPT) 其中：S#为学号，SN为姓名，SEX为性别，AGE为年龄，DEPT为系别，检索所有比“李丽”年龄大的学生姓名和性别。SELECT语句是()

A.SELECT SN，SEX FROM S WHERE AGE＞(SELECT AGE FROM S WHERE SN=“李丽”)

B.SELECT SN，SEX FROM S WHERE SN=“李丽”

C.SELECT SN，SEX FROM S WHERE AGE＞(SELECT AGE WHERE SN=“李丽”)

D.SELECT SN，SEX FROM S WHERE AGE＞李丽.AGE

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更多“假设S(S#，SN，SEX，AGE，DEPT) 其中：S#为…”相关的问题

第1题

给定三个表学生表S，课程表C和学生选课表SC，它们的结构分别如下 S(S，SN，SEX，AGE，DEPT) C(C，CN)

给定三个表学生表S，课程表C和学生选课表SC，它们的结构分别如下：

S(S#，SN，SEX，AGE，DEPT)

C(C#，CN)

SC(S#，C#，GRADE)

其中S#为学号，SN为姓名，SEX为性别，AGE为年龄，DEPT为系别，C#为课程号，CN为课程名，GRADE为成绩。对表SC建立如下视图：CREATE VIEW S_GRADE(S#,C_NUM,AVG_GRADE)AS SELECT S#,COUNT(C#),AVG(GRADE)FROM SCGROUP BY S#;判断下面查询是否允许执行，如允许，写出转换到基本表SC上的操作。SELECT S#，C_NUMFROM S_GRADEWHERE AVG_GRADE80()。

A、不允许查询，因为视图中使用了分组和聚合函数。

B、允许，对应的操作为：

SELECT S#，COUNT(C#)

FROM SC

WHERE AVG(GRADE)80

C、允许，对应的操作为：

SELECT S#,COUNT(C#)

FROM SC

GROUP BY S#

HAVING AVG(GRADE)80

D、允许，对应的操作为：

SELECT S#, COUNT(C#)

FROM SC

HAVING AVG(GRADE)80

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第2题

学生关系模式ST(sno,sname,sex,age)，ST的属性分别表示学生的学号、姓名、性别、年龄。要在表ST中删除属性“年龄”，可选用的SQL语句是()。

学生关系模式ST（sno,sname,sex,age)，ST的属性分别表示学生的学号、姓名、性别、年龄。要在表ST中删除属性“年龄”，可选用的SQL语句是（)。

A.create age from ST

B.alterstable ST drop age

C.update ST age

D.alter table ST drop column age

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第3题

One’s potential is one’s: _______

A.ancestors

B.age

C.possibility

D.preference

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第4题

下列程序段的时间复杂度为()。i=0，s=0;while(sn){s=s+i;i++;}

A.O(n1/2)

B.O(n1/3)

C.O(n)

D.O(n2)

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第5题

使用SQL语句将学生表S中年龄(AGE)大于30岁的记录删除，正确的命令()

A.DELETEFORAGE30

B.DELETEFROMSWHEREAGE30

C.DELETESFORAGE30

D.DELETESWHEREAGE30

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第6题

在一个链接队列中，假设f和r分别是队头和队尾指针，则插入一个s结点的运算时（)。

A.f-＞next=s; f=s;

B.r-＞next=s; r=s;

C.s-＞next=r; r=s;

D.s-＞next=f; f=s;

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第7题

下列说法正确的是（) A.alter table user drop column sex; B.alter table user add sex var

下列说法正确的是()

A.alter table user drop column sex;

B.alter table user add sex varchar(20);

C.alter table user drop sex;

D.alter table user modify id int primary key;

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第8题

假设以S和X分别表示进栈和退栈操作，则对输入序列a,b,c,d,e进行一系列栈操作SSXSXSSXXX之后，得到的输出序列为 a b b c c d d e d c 。()

假设以S和X分别表示进栈和退栈操作，则对输入序列a,b,c,d,e进行一系列栈操作SSXSXSSXXX之后，得到的输出序列为 a b b c c d d e d c 。（)

A.正确

B.错误

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第9题

假设以S和X分别表示进栈和退栈操作，则对输入序列a，b，c，d，e进行一系列栈操作SSXSXSSXXX之后，得到的输出序列为 a b b c c d d e d c 。()

假设以S和X分别表示进栈和退栈操作，则对输入序列a，b，c，d，e进行一系列栈操作SSXSXSSXXX之后，得到的输出序列为 a b b c c d d e d c 。（)

A.正确

B.错误

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第10题

已知指针p和q分别指向某单链表中第一个结点和最后一个结点。假设指针s指向另一个单链表中某个结点，则在s所指结点之后插入上述链表应执行的语句为（)。

A.s-＞next=q;p-＞next=s-＞next

B.s-＞next=p;q-＞next=s-＞next

C.q-＞next=s-＞next;s-＞next=p

D.p-＞next=s-＞next;s-＞next=q

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第11题

Sixteen-year-old Maria was waiting in line at the airport in Santo Domingo. She was

Sixteen-year-old Maria was waiting in line at the airport in Santo Domingo. She was leaving her native country to join her sister in the United States. She spoke English very well. Though she was very happy she could go abroad, she was feeling sad at leaving her family and friends. As she was thinking all about this, she suddenly heard the airline employee asking her to pick up her luggage and put it on the scales (称). Maria pulled and pulled. The bag was too heavy and she just couldn't lift it up. The man behind her got very impatient. He, too, was waiting to check in his luggage.

"What's wrong with this girl？" He said, "Why doesn't she hurry up？" He moved forward and placed his bag on the counter, hoping to check in first. He was in a hurry to get a good seat.

Maria was very angry, but she was very polite. And in her best English she said, "Why are you so upset？ There are enough seats for everyone on the plane. If you are in such a hurry, why can't you give me a hand with my luggage？"

The man was surprised to hear Maria speak English. He quickly picked up her luggage and stepped back. Everyone was looking at him with disapproval.

(5)、The author mentioned Maria's age at the beginning of the story in order to show that _____ .

A.she was young but behaved properly

B.she would not have left home alone

C.everyone around her was wrong

D.it was not good that nobody offered to help her

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