• 2021-04-14
    命令Select S_No,Avg(Grade)As ‘平均成绩’ From Score Group By S_No Having Avg(Grade)>=85,表示
  • 查找Score表中平均成绩在85分以上的学生的学号和平均成绩

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      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;

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      统计选修了a001课程的学生的平均成绩( ) A: select cid,avg(grade) from student group by cid having cid=’a001’ B: select cid,avg(grade) from student where cid=’a001’ group by cid C: select cid,avg(grade) from course where cid=’a001’ group by cid D: select cid,avg(grade) from sc where cid=’a001’ group by cid

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      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;

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      关系SC(Sno,Cno,Grade)表示学号,课程号,成绩。现要查询平均分在90分以上的学生的学号和平均成绩,正确的语句是______。 A: SELECT Sno,AVG(Grad FROM SC WHERE AVG(Grad>=90 GROUP BY Sno B: SELECT Sno,AVG(Grad FROM SC GROUP BY Sno HAVING AVG(Grad>=90 C: SELECT Sno,AVG(Grad FROM SC WHERE AVG(Grad>=90 ORDER BY Sno D: SELECT Sno,AVG(Grad FROM SC GROUP BY Cno HAVING AVG(Grad>=90

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      设关系模式SCG (S#, C#, grade)中S#为学生学号,C#为课程号,grade为某学号学生学某号课程的考试成绩。今要查询每门课程的平均成绩,且要求查询的结果按平均成绩升序排列,平均成绩相同时,按课程号降序排列,则用SQL查询语言应为 (1) 。 若查询的结果仅限于平均分数超过80分的,则应 (2) 。 (1) A: Select C#,AVG(grade) From SCG Group by grade Order by 2,C# Desc B: Select C#,AVG(grade) From SCG Group by C# Order by 2,C# Desc C: Select C#,AVG(grade) From SCG Where C#,AVG Desc Group by grade D: Select C#,AVG(grade) From SCG Group by AVG(grade) Order by 2,C# Desc