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'
举一反三
- 建立信息系选修了1号课程的学生视图，正确的SQL语句为（） A: CREATE VIEW IS_S1 ASSELECT Student.Sno，Sname，Grade FROM Student，SCWHERE Sdept= 'IS' AND Student.Sno=SSno AND SCno= '1'； B: CREATE VIEW IS_S1 (Sno，Sname，Grade) ASSELECT Student.Sno，Sname，Grade FROM Student，SCWHERE Sdept= 'IS' AND SCno= '1'； C: CREATE VIEW IS_S1 (Sno，Sname，Grade) ASSELECT Student.Sno，Sname，GradeFROM Student，SC WHERE Sdept= 'IS' ANDStudent.Sno=SSno AND SCno= '1'
- 建立信息系统学生的视图是（） A: CREATE VIEW is_student AS SELECT sno,sname,sage FROM student WHERE sdpt='is'; B: CREATE VIEW is_student SELECT sno,sname,sageFROM WHERE sdpt='is'; C: CREATE VIEW is_student AS select sno,sname,sage FROM WHERE sdpt='is' D: CREATE VIEW is_student AS SELECT sno,sname,sage WHERE sdpt='is';
- 下列SQL语句中，_________可以在“学生-课程”数据库正确实现“将学生的学号及他的平均成绩定义为一个视图”。 A: CREAT VIEW S_G(Sno，Gavg) AS SELECT Sno，AVG(Grade) FROM SCGROUP BY Sno； B: CREAT VIEW S_G(Sno，AVG(Grade)) AS SELECT Sno，AVG(Grade) FROM SCGROUP BY Sno； C: CREAT VIEW S_G AS SELECT Sno，AVG(Grade) FROM SCGROUP BY Sno； D: CREAT VIEW S_G(Sno，Gavg) AS SELECT Sno，AVG(Grade) FROM SCORDER BY Sno；
- 在学生选课数据库中，查询选修了课程的学生的学号、姓名，SQL语句可为（ ） A: SELECT DISTINCT Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno; B: SELECT Sno, Sname FROM Student, SC WHERE Student.Sno = SC.Sno; C: SELECT DISTINCT Sno, DISTINCT Sname FROM Student WHERE Student.Sno IN (SELECT Sno FROM SC); D: SELECT Sno, Sname FROM Student WHERE Student.Sno IN (SELECT DISTINCT Sno FROM SC);
- 查询每个学生的学号、姓名、选修的课程名及成绩，下列（)的操作是正确的。 A: select student,sno,sname,grade from student,sc where student.sno=sc.sno and sc.cno=course.cno B: select student,sno,sname,grade from student,sc,cource where student.sno=sc.sno C: select student,sno,sname,grade from student,sc,cource where sc.cno=course.cno D: select student,sno,sname,grade from student,sc,cource where student.sno=sc.sno and sc.cno=course.cno
内容
- 0
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));
- 1
有关系S(SNO, SNAME, SAGE)，C(CNO, CNAME)，SC(SNO, CNO, GRADE)。其中SNO是学生号，SNAME是学生姓名，SAGE是学生年龄， CNO是课程号，CNAME是课程名称，GRADE是成绩。以下（ ）SQL语句可以实现查询选修了'C002'号课程的学生姓名。 A: SELECT SNAME FROM S, SC WHERE S.SNO=SC.SNO AND CNO='C002' B: SELECT SNAME FROM S WHERE SNO IN (SELECT SNO FROM SC WHERE CNO='C002') C: SELECT SNAME FROM S WHERE SNO = (SELECT SNO FROM SC WHERE CNO='C002') D: SELECT SNAME FROM S WHERE SNO NOT IN (SELECT SNO FROM SC WHERE CNO='C002')
- 2
以下命令是相关子查询的嵌套查询是： A: SELECT * FROM student WHERE sno IN (SELECT sno FROM sc WHERE cno = '1') B: SELECT * FROM student WHERE EXISTS (SELECT * FROM sc WHERE cno = '1' AND sc.sno = student.sno) C: SELECT sno, cno FROM sc x WHERE grade>(SELECT AVG(grade) FROM sc y WHERE y.sno = x.sno) D: 以上都是
- 3
查询未选修1号课程的同学的姓名,用select sno from studentwhere not exists (select sno from sc where sno=student.sno and cno='1');
- 4
查询没有选数据库基础课程的同学学号和姓名。select sno,sname from student where ____________(select ______ from sc ,course where _______________ and cname='数据库基础') A: not exists；* ; course.cno=sc.cno and student.sno=sno B: not exists；sno ; course.cno=sc.cno and student.sno=sc.sno C: sno not in ; sno ; course.cno=sc.cno D: sno not in ; * ; course.cno=sc.cno and student.sno=sc.sno