【单选题】【消耗次数:1】
删除计算机系学生(在student表中)的修课记录(在SC表中)的语句,正确的是( )。
DELETE FROM SC JOIN Student b ON S.Sno = b.Sno WHERE Sdept = 计算机系
DELETE FROM SC FROM SC JOIN Student b ON SC.Sno = b.Sno WHERE Sdept = 计算机系
DELETE FROM Student WHERE Sdept = 计算机系
DELETE FROM SC WHERE Sdept = 计算机系
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相关题目
【单选题】 下列删除计算机系学生(在student表中)的修课记录(在SC表中)的语句,正确的是( )。
①  DELETEFROM SC JOIN Student b ON S.Sno = b.Sno   WHERE Sdept = 计算机系
②  DELETE FROM SC FROM SC JOIN Student b ON SC.Sno = b.Sno   WHERE Sdept = 计算机系
③  DELETE FROM StudentWHERE Sdept = 计算机系
④  DELETE FROM SC WHERE Sdept = 计算机系
【判断题】 SELECT * FROM Student INNER JOINSC ON Student.Sno = SC.Sno语句可将Student与 SC连接起来。
①  正确
②  错误
【单选题】 对于关系表Student(Sno,Sname,Ssex,Sdept,Sage),以下SQL语句中语法正确的是( )。
①  A.Select Sname From Student Where Sdept=’MA’
②  B.Insert Into Student Values(‘20170001’,’liming’,’男’)
③  C.Delete Sdept From Student Where Sno=’20170002’
④  D.Create View Birthyear_Student as Select Sno,Sname,2019-Sage From Student
【单选题】 设数据库中已有教材中的Student(Sno,Sname,Ssex,Sage,Sdept)、Course(Cno,Cname,Credit,Semster)和SC(Sno,Cno,Grade)表。现要查询学生选的第2学期开设课程的情况,只需列出学号、姓名、所在系和所选的课程号。该查询涉及到的表是( )。
①  仅Student表
②  仅Student和SC表
③  仅Student和Course表
④  Student、SC和Course表
【单选题】 查询计算机系选修了5门以上课程的学生姓名。下面SQL语句中正确的是( )。
①  SELECT 姓名 FROM 选课单 WHERE 系=’计算机’AND COUNT(*)>5
②  SELECT 姓名 FROM 选课单 WHERE 系=’计算机’AND COUNT(*)>5 GROUP BY 姓名
③  SELECT 姓名 FROM 选课单 WHERE 系=’计算机’GROUP BY 姓名 HAVING COUNT(*)>5
④  SELECT 姓名 FROM 选课单 WHERE系=’计算机’GROUP BY 姓名 HAVING系=’计算机’AND COUNT(*)>5
【判断题】 SELECT COUNT(DISTINCT Sno) FROM SC 语句用于统计学生的总人数。
①  正确
②  错误
【单选题】 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, C#是课程号,CNAME是课程名称。要查询选修“ACCESS”课的年龄不小于20的学生姓名,则SQL语句是: SELECTSNAME FROM S,C,SC WHERE子句。 这里的WHERE子句的内容是( )。
①  S.SNO = SC.SNO and C.CNO = SC.CNO and SAGE>=20 and CNAME=‘ACCESS’
②  S.SNO = SC.SNO and C.CNO = SC.CNO and SAGE >=20 and CNAME in ‘ACCESS’
③  SAGE in>=20 and CNAME in ‘ACCESS’
④  SAGE>=20 and CNAME=’ ACCESS’
【单选题】 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, C#是课程号,CNAME是课程名称。要查询选修“ACCESS”课的年龄不小于20的学生姓名,则SQL语句是: SELECTSNAME FROM S,C,SC WHERE子句。 这里的WHERE子句的内容是( )。
①  A.S.SNO = SC.SNO and C.CNO = SC.CNO and SAGE=20 and CNAME=‘ACCESS’
②  B. S.SNO = SC.SNO and C.CNO = SC.CNO and SAGE =20 and CNAME in ‘ACCESS’
③  C. SAGE in=20 and CNAME in ‘ACCESS’
④  D. SAGE=20 and CNAME=’ ACCESS’
【多选题】 设有一个学生选课数据库,其包括学生表S、课程表C和学生选课表SC三个关系: S(SNO, SNAME, SAGE, SSEX, SDEP); C(CNO, CNAME); SC(SNO, CNO, GRADE),其中SNO是学生号,SNAME是学生姓名,SAGE是年龄,SDEP是学生所在系,CNO是课程号,CNAME是课程名称,那么“查询计算机科学系年龄大于19岁的学生”的SQL语句为( )。
①  A.SELECT* FROM S WHERE SDEP = ‘CS’ EXCEPT SELECT* FROM S WHERE SAGE
②  B.SELECT* FROM S WHERE SDEP = CS AND SAGE
③  C.SELECT* FROM S WHERE SDEP = CS AND SAGE
④  D.SELECT* FROM S WHERE SDEP != CS AND SAGE
【单选题】 计算机系统应该包括()
①  主机、键盘、显示器
②  计算机和它的外围设备
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随机题目
【单选题】 16.-This dress was last year’s style. -I think it still looks perfect ______ it has gone out this year.
①  so that
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③  as if
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【单选题】 3.She sent her friend a postcard _______ a birthday present.
①  on
②  as
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【单选题】 19. -Do you remember our pleasant journey to Xi’an? -Of course. I remember everything ______ it happened yesterday.
①  as soon as
②  even though
③  rather than
④  as if
【单选题】 13. Tom failed in the exam again ______ he wanted to pass it very much.
①  if
②  so
③  though
④  as
【单选题】 15.The book was so interesting that he had read it for three hours ______ he realized it.
①  when
②  until
③  after
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②  to
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①  in;to
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③  to; in
④  in; in
【单选题】 20. ______ you can’t answer this question, we have to ask someone else for help.
①  Although
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