• 2022-06-07
    有学生选课表SC(Sno,Cno,Grade),各属性为学号,课程号,成绩;完成SQL语句:找出每个学生超过他选修课平均成绩的课程号。 SELECT Sno,Cno FROM SC X WHERE ______ (SELECT ______ FROM SC Y ______);
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      检索选修了课程”C1”的学生中成绩最高的学生的学号,正确的SELECT语句为( ) A: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE >=ALL (SELECT Grade FROM SC WHERE Cno=’C1’); B: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE IN (SELECT Grade FROM SC WHERE Cno=’C1’); C: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE > ANY (SELECT Grade FROM SC WHERE Cno=’C1’); D: SELECT Sno FROM SC WHERE Cno=’C1’ AND GRADE >= (SELECT Grade FROM SC WHERE Cno=’C1’);

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      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')

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      基于学生—选课—课程数据库中的三个基本表:学生的信息表:STUDENT(sno, sname, sex, age, dept)主码为sno课程信息表:COURSE(cno,cname, teacher)主码为cno学生选课信息表:SC(sno, cno, grade)主码为(sno, cno) “查询没有学习成绩的学生的学号和课程号”的SQL语句是()。 A: SELECT sno, cno FROM SC WHERE grade=NULL B: SELECT sno, cno FROM SC WHERE grade IS" C: SELECT sno, cno FROM SC WHERE grade IS NULL D: SELECT sno, cno FROM SC WHERE grade="

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      ‏检索选修课程“C2”的学生中成绩最高的学生的学号。正确的SELECT语句是()。‍ A: SELECT SNO FROM SC WHERE CNO='C2' AND GRADE >= ( SELECT GRADE FORM SC WHERE CNO='C2' ); B: SELECT SNO FROM SC WHERE CNO='C2' AND GRADE IN ( SELECT GRADE FORM SC WHERE CNO='C2' ); C: SELECT SNO FROM SC WHERE CNO='C2' AND GRADE NOT IN ( SELECT GRADE FORM SC WHERE CNO='C2' ); D: SELECT SNO FROM SC WHERE CNO='C2' AND GRADE >= ALL ( SELECT GRADE FORM SC WHERE CNO='C2' );

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      “查询没有学习成绩的学生的学号和课程号”的SQL语 句是( ) (2.0) A: SELECT sno,cno FROM SC WHERE grade = NULL B: SELECT sno,cno FROM SC WHERE grade IS ' ' C: SELECT sno,cno FROM SC WHERE grade IS NULL D: SELECT sno,cno FROM SC WHERE grade = ' '