• 2022-10-26
    已知关系模式:SC(sno,sname,grade),各属性含义依次为学号、课程名、分数。要查找“数据库”课分数最高的学生的学号,正确的SQL语句是( )。
    A: SELECT sno FROM sc WHERE sname="数据库"AND grade=MAX(grade)
    B: SELECT sno FROM sc FOR sname="数据库"OR grade>=MAX(grade)
    C: SELECT sno FROM sc WHERE sname="数据库"AND grade=(SELECT MAX(grade)FROM sc)
    D: SELECT sno FROM sc FOR sname="数据库"OR grade=(SELECT MAX(grade)FROM s
  • C

    举一反三

    内容

    • 0

      有如下的SQL语句.Ⅰ. SELECT sname FROM s, sc WHERE gradeⅡ. SELECT sname FROM s WHERE sno IN(SELECT sno FROM sc WHERE gradeⅢ. SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade若要查找分数(grade)不及格的学生姓名(sname),则以上正确的有哪些?( ) 。 A: Ⅰ和Ⅱ B: Ⅰ和Ⅲ C: Ⅱ和Ⅲ D: Ⅰ、Ⅱ和Ⅲ

    • 1

      有如下的SQL语句:Ⅰ. SELECT sname FROM s, sc WHERE grade<;60Ⅱ. SELECT sname FROM s WHERE sno IN(SELECT sno FROM sc WHERE grade<;60)Ⅲ. SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade<;60若要查找分数(grade)不及格的学生姓名(sname),则以上正确的有哪些?() A: Ⅰ和Ⅱ B: Ⅰ和Ⅲ C: Ⅱ和Ⅲ D: Ⅰ、Ⅱ和Ⅲ

    • 2

      有关系S(S#,SNAME,SAGE),C(C#,CNAME),SC(S#,C#,GRADE)。若要查找分数(grade)不及格的学生姓名(sname),则以上正确的有?( ) A: SELECT sname FROM s, sc WHERE grade<60 B: SELECT sname FROM s WHERE sno IN(SELECT Cno FROM sc WHERE grade<60) C: SELECT sname FROM s, sc WHERE s.sno=sc.sno AND grade<60 D: SELECT sname FROM s, sc WHERE s.sno=sc.sno OR grade<60

    • 3

      关系SC(Sno,Cno,Grade)表示学号、课程号、成绩。现要查询最高分在91分以上的学生的学号和平均成绩,正确的语句是______。 A: SELECT Sno,MAX(Grade)<br> FROM SC<br> WHERE MAX(Grade)≥91<br> GROUP BY Sno B: SELECT Sno,MAX(Grade)<br> FROM SC<br> GROUP BY Sno<br> HAVING MAX(Grade)≥91 C: SELECT Sno,MAX(Grade)<br> FROM SC<br> WHERE MAX(Grade)≥91<br> ORDER BY Sno D: SELECT Sno,MAX(Grade)<br> FROM SC<br> GROUP BY Cno<br> HAVING MAX(Grade)≥91

    • 4

      针对表SC(sno, cno, grade),其中sno为学号,cno为课程号,grade为成绩。以下哪个操作( )统计出每位学生所选课程的最高分和最低分。 A: select sno,max(grade), min(grade) from sc B: select sno,max(grade), min(grade) from sc order by sno C: select sno,max(grade), min(grade) from sc group by sno D: select sno,avg(grade), sum(grade) from sc group by sno