• 2022-10-26
    在学生选课数据库中,查询平均成绩大于等于60分的同学,SQL语句为( )
    A: SELECT Sno, AVG(Grade) FROM SC GROUP BY Sno HAVING AVG(Grade)>=60;
    B: SELECT Sno FROM SC WHERE Grade>=60 GROUP BY Sno;
    C: SELECT Sno, Grade FROM SC GROUP BY Sno HAVING AVG(Grade)>=60;
    D: SELECT Sno FROM SC GROUP BY Sno HAVING Grade >=60;
  • A

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      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

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      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

    • 2

      查询平均成绩小于70分的学生学号和平均成绩 A: SELECT Sno, AVG(grade) FROM  SC GROUPBYSno B: SELECT Sno, AVG(grade) FROM  SC GROUPBYSno  HAVINGAVG(grade)<70; C: SELECT Sno, grade FROM  SC GROUPBYSno HAVINGAVG(grade)<70;

    • 3

      设有关系模式:SC(sno,cno,grade),各属性含义依次是学号、课程号、分数。要查询分数低于60分的学生学号,正确的SQL语句是______。 A: SEI,ECT sno FROM SC WH ERE grade BETWEEN O AND 60 B: SELECT sno FROM SC WHERE grade<60 C: SELECT sno FROM SC HAVlNG grade BETWEEN O AND 60 D: SELECT sno FROM SC HAVING grade<60

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      针对学生选课表sc(sno, cno, grade),其中sno为学号,cno为课程号,grade为成绩。以下( )语句可查询选修了两门以上成绩在90分以上课程的学生学号。 A: select sno from sc where grade&gt;90 group by sno having count(cno)&gt;2; B: select sno from sc where grade&gt;90 group by sno having count(*)&gt;2; C: select sno from sc where grade&gt;90 and count(*)&gt;2 group by sno; D: select sno from sc where grade&gt;90 group by sno having count(sno)&gt;2;