点击查看：2018年全国计算机三级数据库技术章节题及答案汇总
第6章 高级数据查询
1[单选题] 设在某SELECT语句的WHERE子句中，需要对Grade列的空值进行处理。下列关于空值的操作中，错误的是__________。
A.Grade IS NOT NULL
B.Grade IS NULL
C.Grade = NULL
D.NOT (Grade IS NULL)
参考答案：C
2[单选题]
现要利用Student表查询年龄最小的学生的姓名和年龄。下列实现此功能的查询语句中，正确的是__________。
A.SELECT Sname, MIN(Sage) FROM Student
B.SELECT Sname, Sage FROM Student WHERE Sage = MIN(Sage)
C.SELECT TOP 1 Sname, Sage FROM Student
D.SELECT TOP 1 Sname, Sage FROM Student ORDER BY Sage
参考答案：D
3[单选题]
设SC表中记录成绩的列为：Grade，类型为int。若在查询成绩时，希望将成绩按“优”、“良”、“中”、“及格”和“不及格”形式显示，正确的Case函数是__________。
A.Case GradeWhen 90～100 THEN'优'When 80～89 TIIEN'良'When 70～79 THEN'中'When 60～69 THEN'及格'。 Else'不及格’End
B.CaseWhen 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 GradeWhen 90～100 THEN Grade='优’When 80～89 THEN Grade='良’When 70～79 THEN Grade='由’When 60～69 THEN Grade='及格’Else Grade='不及格’End
参考答案：C
4[单选题]
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__________。
A.select sno,sname, sage from student where sdept = 'cs 'Order by sageUnionselect sno,sname,sage from student where sdept = 'is'Order by sage
B.select sno,sname, sage from student where sdept = 'cs 'Unionselect sno,sname, sage from student where sdept = 'is 'Order by sage
C.select sno,sname,sage from student where sdept = 'cs 'Unionselect sno,sname from student where sdept = 'is'Order by sage
D.select sno,sname,sage from student where sdept = 'cs'Order by sageUnionselect sno,shame, sage fron student where sdept = 'is'
参考答案：B
5[单选题]
在SQL Server 2000中，有学生表(学号，姓名，年龄)，其中“姓名”的数据类型是：char(10)。现要查询姓“张”且名字是三个字的学生的详细信息，正确的语句是__________。
A.SELECT*FROM学生表WHERE姓名LIKE'张_’
B.SELECT*FROM学生表WHERE姓名LIKE'张_’
C.SELECT*FROM学生表WHERE姓名LIKE'张_'AND LEN(姓名)=3
D.SELECT*FROM学生表WHERE姓名LIKE'张_'AND LEN(姓名)=4
参考答案：C
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