急求！！！用SQL查询学生的所有选课信息的语句该怎么写？前面已经建好了Student、Course和SC的表了

发布网友发布时间：2022-04-09 09:39

共2个回答

懂视网时间：2022-04-09 14:01

a.s# FROM ( SELECT * FROM dbo.SC WHERE c# = ‘001‘ ) a INNER JOIN ( SELECT * FROM dbo.SC WHERE c# = ‘002‘ ) b ON a.s# = b.s# WHERE a.score > b.score

2、查询平均成绩大于60分的同学的学号和平均成绩;

SELECT s# ,
 AVG(score)
FROM dbo.SC
GROUP BY s#
HAVING AVG(score) > 60

3、查询所有同学的学号、姓名、选课数、总成绩;

SELECT a.s# ,
 a.sname ,
 COUNT(b.c#) ,
 SUM(b.score)
FROM dbo.Student a
 LEFT OUTER JOIN dbo.SC b ON a.s# = b.s#
GROUP BY a.s# ,
 a.sname

4、查询姓“李”的老师的个数;

SELECT COUNT(DISTINCT tname)
FROM dbo.Teacher
WHERE tname LIKE ‘李%‘

5、查询没学过“叶平”老师课的同学的学号、姓名;

SELECT Student.S# ,
 Student.Sname
FROM Student
WHERE S# NOT IN ( SELECT DISTINCT
    ( SC.S# )
   FROM SC ,
    Course ,
    Teacher
   WHERE SC.C# = Course.C#
    AND Teacher.T# = Course.T#
    AND Teacher.Tname = ‘叶平‘ )

6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名;

SELECT Student.S# ,
 Student.Sname
FROM Student ,
 SC
WHERE Student.S# = SC.S#
 AND SC.C# = ‘001‘
 AND EXISTS ( SELECT *
   FROM SC AS SC_2
   WHERE SC_2.S# = SC.S#
    AND SC_2.C# = ‘002‘ )

7、查询学过“叶平”老师所教的所有课的同学的学号、姓名;

SELECT S# ,
 Sname
FROM Student
WHERE S# IN ( SELECT S#
  FROM SC ,
   Course ,
   Teacher
  WHERE SC.C# = Course.C#
   AND Teacher.T# = Course.T#
   AND Teacher.Tname = ‘叶平‘
  GROUP BY S#
  HAVING COUNT(SC.C#) = ( SELECT COUNT(C#)
      FROM Course ,
      Teacher
      WHERE Teacher.T# = Course.T#
      AND Tname = ‘叶平‘
     ) )

8、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名;

SELECT S# ,
 Sname
FROM ( SELECT Student.S# ,
   Student.Sname ,
   score ,
   ( SELECT score
   FROM SC SC_2
   WHERE SC_2.S# = Student.S#
    AND SC_2.C# = ‘002‘
   ) score2
  FROM Student ,
   SC
  WHERE Student.S# = SC.S#
   AND C# = ‘001‘
 ) S_2
WHERE score2 < score

9、查询所有课程成绩小于60分的同学的学号、姓名;

SELECT S# ,
 Sname
FROM Student
WHERE S# NOT IN ( SELECT Student.S#
   FROM Student ,
    SC
   WHERE Student.S# = SC.S#
    AND score > 60 )

10、查询没有学全所有课的同学的学号、姓名;

SELECT Student.S# ,
 Student.Sname
FROM Student ,
 SC
WHERE Student.S# = SC.S#
GROUP BY Student.S# ,
 Student.Sname
HAVING COUNT(C#) < ( SELECT COUNT(C#)
   FROM Course
   )

11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名;

SELECT S# ,
 Sname
FROM Student ,
 SC
WHERE Student.S# = SC.S#
 AND C# IN ( SELECT C#
   FROM SC
   WHERE S# = ‘1001‘ )

12、查询至少学过学号为“001”同学所有一门课的其他同学学号和姓名;

SELECT DISTINCT
 SC.S# ,
 Sname
FROM Student ,
 SC
WHERE Student.S# = SC.S#
 AND C# IN ( SELECT C#
   FROM SC
   WHERE S# = ‘001‘ )

13、把“SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩;

UPDATE SC
SET score = ( SELECT AVG(SC_2.score)
   FROM SC SC_2
   WHERE SC_2.C# = SC.C#
  )
FROM Course ,
 Teacher
WHERE Course.C# = SC.C#
 AND Course.T# = Teacher.T#
 AND Teacher.Tname = ‘叶平‘

14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名;

SELECT S#
FROM SC
WHERE C# IN ( SELECT C#
  FROM SC
  WHERE S# = ‘1002‘ )
GROUP BY S#
HAVING COUNT(*) = ( SELECT COUNT(*)
   FROM SC
   WHERE S# = ‘1002‘
   )

15、删除学习“叶平”老师课的SC表记录;

DELETE SC
FROM course ,
 Teacher
WHERE Course.C# = SC.C#
 AND Course.T# = Teacher.T#
 AND Tname = ‘叶平‘

16、向SC表中插入一些记录，这些记录要求符合以下条件：没有上过编号“003”课程的同学学号、2、号课的平均成绩;

INSERT SC
 SELECT S# ,
  ‘002‘ ,
  ( SELECT AVG(score)
   FROM SC
   WHERE C# = ‘002‘
  )
 FROM Student
 WHERE S# NOT IN ( SELECT S#
    FROM SC
    WHERE C# = ‘002‘ )

17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩，按如下形式显示：学生ID,,数据库,企业管理,英语,有效课程数,有效平均分

SELECT S# AS 学生ID ,
 ( SELECT score
  FROM SC
  WHERE SC.S# = t.S#
   AND C# = ‘004‘
 ) AS 数据库 ,
 ( SELECT score
  FROM SC
  WHERE SC.S# = t.S#
   AND C# = ‘001‘
 ) AS 企业管理 ,
 ( SELECT score
  FROM SC
  WHERE SC.S# = t.S#
   AND C# = ‘006‘
 ) AS 英语 ,
 COUNT(*) AS 有效课程数 ,
 AVG(t.score) AS 平均成绩
FROM SC AS t
GROUP BY S#
ORDER BY AVG(t.score)

18、查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，最低分

SELECT L.C# AS 课程ID ,
 L.score AS 最高分 ,
 R.score AS 最低分
FROM SC L ,
 SC AS R
WHERE L.C# = R.C#
 AND L.score = ( SELECT MAX(IL.score)
   FROM SC AS IL ,
    Student AS IM
   WHERE L.C# = IL.C#
    AND IM.S# = IL.S#
   GROUP BY IL.C#
   )
 AND R.Score = ( SELECT MIN(IR.score)
   FROM SC AS IR
   WHERE R.C# = IR.C#
   GROUP BY IR.C#
   )

19、按各科平均成绩从低到高和及格率的百分数从高到低顺序

SELECT t.C# AS 课程号 ,
 MAX(course.Cname) AS 课程名 ,
 ISNULL(AVG(score), 0) AS 平均成绩 ,
 100 * SUM(CASE WHEN ISNULL(score, 0) >= 60 THEN 1
   ELSE 0
   END) / COUNT(*) AS 及格百分数
FROM SC T ,
 Course
WHERE t.C# = course.C#
GROUP BY t.C#
ORDER BY 100 * SUM(CASE WHEN ISNULL(score, 0) >= 60 THEN 1
   ELSE 0
   END) / COUNT(*) DESC

20、查询如下课程平均成绩和及格率的百分数(用"1行"显示): 企业管理（001），马克思（002），OO&UML （003），数据库（004）

SELECT SUM(CASE WHEN C# =‘001‘ THEN score ELSE 0 END)/SUM(CASE C# WHEN ‘001‘ THEN 1 ELSE 0 END) AS 企业管理平均分 
,100 * SUM(CASE WHEN C# = ‘001‘ AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = ‘001‘ THEN 1 ELSE 0 END) AS 企业管理及格百分数 
,SUM(CASE WHEN C# = ‘002‘ THEN score ELSE 0 END)/SUM(CASE C# WHEN ‘002‘ THEN 1 ELSE 0 END) AS 马克思平均分 
,100 * SUM(CASE WHEN C# = ‘002‘ AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = ‘002‘ THEN 1 ELSE 0 END) AS 马克思及格百分数 
,SUM(CASE WHEN C# = ‘003‘ THEN score ELSE 0 END)/SUM(CASE C# WHEN ‘003‘ THEN 1 ELSE 0 END) AS UML平均分 
,100 * SUM(CASE WHEN C# = ‘003‘ AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = ‘003‘ THEN 1 ELSE 0 END) AS UML及格百分数 
,SUM(CASE WHEN C# = ‘004‘ THEN score ELSE 0 END)/SUM(CASE C# WHEN ‘004‘ THEN 1 ELSE 0 END) AS 数据库平均分 
,100 * SUM(CASE WHEN C# = ‘004‘ AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = ‘004‘ THEN 1 ELSE 0 END) AS 数据库及格百分数 
FROM SC

21、查询不同老师所教不同课程平均分从高到低显示

SELECT max(Z.T#) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.C# AS 课程ＩＤ,MAX(C.Cname) AS 课程名称,AVG(Score) AS 平均成绩 
FROM SC AS T,Course AS C ,Teacher AS Z 
where T.C#=C.C# and C.T#=Z.T# 
GROUP BY C.C# 
ORDER BY AVG(Score) DESC

22、查询如下课程成绩第 3 名到第 6 名的学生成绩单：企业管理（001），马克思（002），UML （003），数据库（004） [学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩

SELECT DISTINCT top 3 
SC.S# As 学生学号, 
Student.Sname AS 学生姓名 , 
T1.score AS 企业管理, 
T2.score AS 马克思, 
T3.score AS UML, 
T4.score AS 数据库, 
ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 总分 
FROM Student,SC LEFT JOIN SC AS T1 
ON SC.S# = T1.S# AND T1.C# = ‘001‘ 
LEFT JOIN SC AS T2 
ON SC.S# = T2.S# AND T2.C# = ‘002‘ 
LEFT JOIN SC AS T3 
ON SC.S# = T3.S# AND T3.C# = ‘003‘ 
LEFT JOIN SC AS T4 
ON SC.S# = T4.S# AND T4.C# = ‘004‘ 
WHERE student.S#=SC.S# and 
ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) 
NOT IN 
(SELECT 
DISTINCT 
TOP 15 WITH TIES 
ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) 
FROM sc 
LEFT JOIN sc AS T1 
ON sc.S# = T1.S# AND T1.C# = ‘k1‘ 
LEFT JOIN sc AS T2 
ON sc.S# = T2.S# AND T2.C# = ‘k2‘ 
LEFT JOIN sc AS T3 
ON sc.S# = T3.S# AND T3.C# = ‘k3‘ 
LEFT JOIN sc AS T4 
ON sc.S# = T4.S# AND T4.C# = ‘k4‘ 
ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC)

23、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60]

SELECT SC.C# as 课程ID, Cname as 课程名称 
,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85] 
,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70] 
,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60] 
,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS [60 -] 
FROM SC,Course 
where SC.C#=Course.C# 
GROUP BY SC.C#,Cname

24、查询学生平均成绩及其名次

SELECT 1+(SELECT COUNT( distinct 平均成绩) 
FROM (SELECT S#,AVG(score) AS 平均成绩 
FROM SC 
GROUP BY S# 
) AS T1 
WHERE 平均成绩 > T2.平均成绩) as 名次, 
S# as 学生学号,平均成绩 
FROM (SELECT S#,AVG(score) 平均成绩 
FROM SC 
GROUP BY S# 
) AS T2 
ORDER BY 平均成绩 desc

25、查询各科成绩前三名的记录:(不考虑成绩并列情况)

SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数 
FROM SC t1 
WHERE score IN (SELECT TOP 3 score 
FROM SC 
WHERE t1.C#= C# 
ORDER BY score DESC 
) 
ORDER BY t1.C#;

26、查询每门课程被选修的学生数

select c#,count(S#) from sc group by C#;

27、查询出只选修了一门课程的全部学生的学号和姓名

select SC.S#,Student.Sname,count(C#) AS 选课数 
from SC ,Student 
where SC.S#=Student.S# group by SC.S# ,Student.Sname having count(C#)=1;

28、查询男生、女生人数

Select count(Ssex) as 男生人数 from Student group by Ssex having Ssex=‘男‘; 
Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex=‘女‘;

29、查询姓“张”的学生名单

SELECT Sname FROM Student WHERE Sname like ‘张%‘;

30、查询同名同性学生名单，并统计同名人数

select Sname,count(*) from Student group by Sname having count(*)>1;;

31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)

select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age 
from student 
where CONVERT(char(11),DATEPART(year,Sage))=‘1981‘;

32、查询每门课程的平均成绩，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

Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;

33、查询平均成绩大于85的所有学生的学号、姓名和平均成绩

select Sname,SC.S# ,avg(score) 
from Student,SC 
where Student.S#=SC.S# group by SC.S#,Sname having avg(score)>85;

34、查询课程名称为“数据库”，且分数低于60的学生姓名和分数

Select Sname,isnull(score,0) 
from Student,SC,Course 
where SC.S#=Student.S# and SC.C#=Course.C# and Course.Cname=‘数据库‘and score <60;

35、查询所有学生的选课情况;

SELECT SC.S#,SC.C#,Sname,Cname 
FROM SC,Student,Course 
where SC.S#=Student.S# and SC.C#=Course.C# ;

36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数;

SELECT distinct student.S#,student.Sname,SC.C#,SC.score 
FROM student,Sc 
WHERE SC.score>=70 AND SC.S#=student.S#;

37、查询不及格的课程，并按课程号从大到小排列

select c# from sc where score <60 order by C# ;

38、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名;

select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#=‘003‘;

39、求选了课程的学生人数

select count(*) from sc;

40、查询选修“叶平”老师所授课程的学生中，成绩最高的学生姓名及其成绩

select Student.Sname,score 
from Student,SC,Course C,Teacher 
where Student.S#=SC.S# and SC.C#=C.C# and C.T#=Teacher.T# and Teacher.Tname=‘叶平‘ and SC.score=(select max(score)from SC 
 var cpro_id = "u6292429";
 



                                        
                        
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                        时间：2022-04-09 11:09
                    
                    select student.sname,course.cname--查询学生名，课程名
from student,course,sc where student.sno=sc.sno and course.cno=sc.cno--三个表之间的关联
order by student.sname --按姓名排序
字段名有跟你不一样的，自行修改一下