选择题：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 SnameFROM StudentWHERE Sage >; (SELECT AVG(Sage)FROM Student);WHERE Sdept = 'CS' B: SELECT SnameFROM StudentWHERE Sage >; AVG(SELECT SageFROM StudentWHERE Sdept = 'CS'); C: SELECT SnameFROM StudentWHERE Sage >; (SELECT AVG(Sage)FROM StudentWHERE Sdept = 'CS'); D: SELECT SnameFROM StudentWHERE AVG(Sage) >; (SELECT SageFROM StudentWHERE Sdept = 'CS');

选择题：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 SnameFROM StudentWHERE Sage > (SELECT AVG(Sage)FROM Student);WHERE Sdept = 'CS' B: SELECT SnameFROM StudentWHERE Sage > AVG(SELECT SageFROM StudentWHERE Sdept = 'CS'); C: SELECT SnameFROM StudentWHERE Sage > (SELECT AVG(Sage)FROM StudentWHERE Sdept = 'CS'); D: SELECT SnameFROM StudentWHERE AVG(Sage) > (SELECT SageFROM StudentWHERE Sdept = 'CS');

要求查询“student表中在1999年以后出生的学生信息”，以下SQL语句正确的是： A: select *from student; B: select *from studentwhere 生日 > 1999年; C: select *from studentwhere 生日 >= '1999-1-1' D: select *from studentwhere 生日 >= 1999-1-1;

‏下列SQL语句，_____________可以在“学生-课程”数据库正确实现“查询年龄在20-23岁（包括20岁和23岁）之间的学生的姓名、系别和年龄”。‍ A: SELECT Sname，Sdept，SageFROM StudentWHERE Sage BETWEEN 20 AND 23 B: SELECT Sname，Sdept，SageFROM StudentWHERE Sage 20 AND 23 C: SELECT Sname，Sdept，SageFROM StudentWHERE Sage >=20 AND <=23 D: SELECT Sname，Sdept，SageFROM StudentWHERE Sage NOT BETWEEN 20 AND 23

针对数据库S_T，以下创建视图的命令不正确的是（ ）。 A: create view view1asselect sno,avg(grade)from scgroup by sno B: create view view2asselect sno,sname,sdeptfrom studentwhere sdept='CS' C: create view view3asselect sno,sage+20from studentwhere ssex='女' D: create view view4asselect student.sno,sname,sc.sno,cno,grade from sc,studentwhere sc.sno=student.sno and cno='1'

查询计算机系任意学生选修过的课程号，不正确的查询语句是： A: SELECT DISTINCT CnoFROM SCWHERE NOT EXISTS (SELECT SnoFROM StudentWHERE Sdept = 'CS'AND SSno = Student.Sno); B: SELECT DISTINCT CnoFROM SCWHERE EXISTS (SELECT SnoFROM StudentWHERE Sdept = 'CS'AND SSno = Student.Sno); C: SELECT DISTINCT CnoFROM SCWHERE Sno IN (SELECT SnoFROM StudentWHERE Sdept = 'CS'); D: SELECT DISTINCT CnoFROM SCLEFT JOIN StudentON SSno = Student.SnoWHERE Sdept = 'CS';

查询计算机系任意学生选修过的课程号，不正确的查询语句是： A: SELECT DISTINCT CnoFROM SCWHERE NOT EXISTS (SELECT SnoFROM StudentWHERE Sdept = 'CS'AND SC.Sno = Student.Sno); B: SELECT DISTINCT CnoFROM SCWHERE EXISTS (SELECT SnoFROM StudentWHERE Sdept = 'CS'AND SC.Sno = Student.Sno); C: SELECT DISTINCT CnoFROM SCWHERE Sno IN (SELECT SnoFROM StudentWHERE Sdept = 'CS'); D: SELECT DISTINCT CnoFROM SCLEFT JOIN StudentON SC.Sno = Student.SnoWHERE Sdept = 'CS';

查询非计算机系中比计算机系中年龄最小者年龄大或相等的学生姓名，不正确的查询语句是： A: SELECT SnameFROM Student S1WHERE NOT EXISTS (SELECT *FROM Student S2WHERE S2.Sdept = 'CS'AND S1.Sage ;= S2.Sage)AND Sdept != 'CS'; B: SELECT SnameFROM StudentWHERE Sage >;= (SELECT MIN(Sage) FROMStudentWHERE Sdept = 'CS')AND Sdept != 'CS'; C: SELECT SnameFROM StudentWHERE Sage >;= ANY (SELECT SageFROM StudentWHERE Sdept = 'CS')AND Sdept != 'CS';

下面的SQL语句也可以用带Join关键词的语句来实现。Select Student.Sno,Student.Sname, SC.Cno,SC.GradeFrom SC,StudentWhere SC.Sno=Student.Sno

查询计算机系任意学生选修过的课程号，可以使用如下语句：SELECT DISTINCT CnoFROM SCWHERE Sno IN (SELECT SnoFROM StudentWHERE Sdept = 'CS');