下列查询中,属于相关子查询的有（）。 A: SELECT * FROM student WHERE sno IN (SELECT sno FROM sc WHERE cno='1'); B: SELECT sno, cno FROM SC x WEHRE grade>=(SELECT AVG(grade) FROM SC y WHERE y.sno = x.sno); C: SELECT sname FROM student WHERE EXISTS(SELECT * FROM sc WHERE sno=student.sno AND cno='1'); D: SELECT sname FROM student WHERE NOT EXISTS(SELECT * FROM course WHERE NOT EXISTS(SELECT * FROM sc WHERE sc.sno=student.sno AND sc.cno=course.cno));

下列的查询语句哪一项是错误的（选一项） A: Select * from stumarks where score>=60 B: Select * from (select * from stumarks where score>=60) C: Select * from (select * from stumarks where score>=60) as temp D: Select * from (select * from stumarks ) as temp where score>=60

查询所有成绩均大于80分的学生姓名,应执行( )语句 A: SELECT SNAME FROM STUDENT WHERE EXISTS (SELECT *FROM SC WHERE STUDENSNO = SC.SNO AND GRADE> 80); B: SELECT SNAME FROM STUDENT WHERE EXISTS (SELECT *FROM SC WHERE STUDENSNO = SC.SNO AND GRADE C: SELECT SNAME FROM STUDENT WHERE NOT EXISTS (SELECT *FROM SC WHERE STUDENSNO = SC.SNO AND GRADE D: SELECT SNAME FROM STUDENT WHERE NOT EXISTS (SELECT *FROM SC WHERE STUDENSNO = SC.SNO AND GRADE> 80);

查询没有借阅图书编号为“b0003”的学生姓名。不能得到正确结果的SELECT语句是( ). A: SELECT 姓名FROM 学生 <br>WHERE NOT EXISTS( SELECT * FROM 借阅 WHERE (学生.学号=学号) AND (书号=’b0003’)) B: SELECT 姓名FROM 学生 WHERE 学号 !=ANY ( SELECT 学号 FROM 借阅 WHERE 书号=’b0003’) C: SELECT 姓名FROM 学生 WHERE 学号 NOT IN ( SELECT 学号 FROM 借阅 WHERE 书号=’b0003’) D: SELECT 姓名FROM 学生 <br>WHERE 学号 !=ALL ( SELECT 学号 FROM 借阅 WHERE 书号=’b0003’)

查询成绩大于90分的学生的姓名，正确的SQL命令是（ ） A: select 姓名 from 学生表 where 学号=(select 学号 from 成绩表 where 成绩>90) B: select 姓名 from 学生表 where 学号 in (select 学号 from 成绩表 where 成绩>90) C: select 姓名 from 学生表 where 学号>(select 学号 from 成绩表 where 成绩>90) D: select 姓名 from 学生表 where 学号90)

下列 SQL 语句select * from student where sno = '05880101'union select * from student where sno = '05880102'与此查询语句等价的选项是( )。 A: select * from student where sno= '05880101' and sno= '05880102' B: select * from student where sno= '05880101' or sno= '05880102' C: select * from student where sno= '05880101' D: select * from student where sno= '05880102'

下列有关子菜单的说法中，错误的是（ ）。 A: SELECT姓名FROM学生表WHERE EXISTS；(SELECT学号FROM成绩表WHERE成绩＞90) B: SELECT姓名FROM学生表WHERE EXISTS；(SELECT学号FROM成绩表WHERE学号=学生表．学号AND成绩＞90) C: SELECT姓名FROM学生表WHERE学号EXISTS；(SELECT学号FROM成绩表WHERE学号=学生表．学号AND成绩＞90) D: SELECT姓名FROM学生表WHERE学号=；(SELECT学号FROM成绩表WHERE成绩＞90)

在所有学生中查询比计算机系学生平均年龄大的学生姓名，可以使用的查询语句是： A: SELECT Sname FROM Student WHERE Sage > ( SELECT AVG(Sage) FROM Student ); WHERE Sdept = 'CS' B: SELECT Sname FROM Student WHERE Sage > AVG( SELECT Sage FROM Student WHERE Sdept = 'CS' ); C: SELECT Sname FROM Student WHERE Sage > ( SELECT AVG(Sage) FROM Student WHERE Sdept = 'CS' ); D: SELECT Sname FROM Student WHERE AVG(Sage) > ( SELECT Sage FROM Student WHERE Sdept = 'CS' );

下列SELECT语句中正确的是（ ）。 A: SELECT * FROM 学生表 WHERE 姓名="张三" B: SELECT * FROM "学生表" WHERE 姓名="张三" C: SELECT * FROM "学生表" WHERE 姓名=张三 D: SELECT * FROM 学生表 WHERE 姓名=张三

从"产品"表中查找出单价低于"产品编号"为"431"的记录，正确的SQL命令是（）。 A: SELECT * FROM 产品 WHERE 单价<;(SELECT * FROM 产品 WHERE 产品编号="431") B: SELECT * FROM 产品 WHERE 单价<;(SELECT 单价 FROM 产品 WHERE 产品编号="431") C: SELECT * FROM 产品 WHERE 单价<;"431" D: SELECT * FROM 产品 WHERE EXISTS单价="431"