假如有两个表的连接是这样的:table_1 RIGHT JOIN table_2 其中table_1和table_2是两个具有公共属性的表,这种连接会生成( 2 )的结果集。
A. 包括table_1中的所有行,不包括table_2的不匹配行
B. 包括table_2中的所有行,不包括table_1的不匹配行
C. 包括两个表的所有行
D. 只包括table_1和table_2满足条件的行
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下面()关键字不影响SELECT语句返回的结果的行数。
A. TOP n
B. ORDER BY
C. WHERE
DISTINCT
select * from student where sno like '010_[^1]%[A-B]_',可能会查询出的sno是()。
A. 01051090A109
B. 01001090A011
C. 0105309011B0
D. 0101111A0111
与查询Select * from student where sage> (select max(sage) from student where ssex='男')等价的语句是()。
A. Select * from student where sage> any (select sage from student where ssex='男')
B. Select max(sage) from student where ssex='男'
C. Select * from student where sage in (select sage from student where ssex='男')
D. Select * from student where sage> all (select sage from student where ssex='男')
与查询Select student.* from student,grade Where student.sno=grade.sno and grade.score>90等价的语句是()。
A. Select * from student Where exists (select sno from grade where score>90)
B. Select * from student Where sno exists (select sno from grade where score>90)
C. Select student.* from student,grade Where grade.score>90
D. Select * from student Where sno in (select sno from grade where score>90)
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