数据库原理及应用(第2版)--课后习题参考答案(9)

When Grade between 90 and 100 THEN Grade = '优'

When Grade between 80 and 89 THEN Grade = '良'

When Grade between 70 and 79 THEN Grade = '中'

When Grade between 60 and 69 THEN Grade = '及格'

Else Grade = '不及格'

End

C. Case

When Grade between 90 and 100 THEN '优'

When Grade between 80 and 89 THEN '良'

When Grade between 70 and 79 THEN '中'

When Grade between 60 and 69 THEN '及格'

Else '不及格'

End

D. Case Grade

When 90~100 THEN Grade = '优'

When 80~89 THEN Grade = '良'

When 70~79 THEN Grade = '中'

When 60~69 THEN Grade = '及格'

Else Grade = '不及格'

End

8．下述语句的功能是将两个查询结果合并为一个结果。其中正确的是 B

A．select sno,sname,sage from student where sdept = 'cs'

Order by sage

Union

select sno,sname,sage from student where sdept = 'is'

Order by sage

B．select sno,sname,sage from student where sdept = 'cs'

Union

select sno,sname,sage from student where sdept = 'is'

Order by sage

C．select sno,sname,sage from student where sdept = 'cs'

Union

select sno,sname from student where sdept = 'is'

Order by sage

D．select sno,sname,sage from student where sdept = 'cs'

Order by sage

Union

select sno,sname,sage from student where sdept = 'is'

9．下列SQL语句中，用于修改表数据的语句是 C

A．ALTER B．SELECT

C．UPDATE D．INSERT

10．设有Teachers表，该表的定义如下：

CREATE TABLE Teachers(

百度搜索“77cn”或“免费范文网”即可找到本站免费阅读全部范文。收藏本站方便下次阅读，免费范文网，提供经典小说教育文库数据库原理及应用(第2版)--课后习题参考答案(9)在线全文阅读。