50个常用sql语句 网上流行的学生选课表的例子

50个常用sql语句

建表：

--学生表tblStudent（编号StuId、姓名StuName、年龄StuAge、性别StuSex）

--课程表tblCourse（课程编号CourseId、课程名称CourseName、教师编号TeaId）

--成绩表tblScore（学生编号StuId、课程编号CourseId、成绩Score）

--教师表tblTeacher（教师编号TeaId、姓名TeaName）

问题：

1、查询“001”课程比“002”课程成绩高的所有学生的学号;

select a.StuId from (select StuId,Score from tblScore where CourseId='001') a,(select StuId,Score

from tblScore where CourseId='002') b

where a.Score>b.Score and a.StuId=b.StuId;

2、查询平均成绩大于60分的同学的学号和平均成绩;

select StuId,avg(Score)

from tblScore

group by StuId having avg(Score) >60;

3、查询所有同学的学号、姓名、选课数、总成绩;

select tblStudent.StuId,tblStudent.StuName,count(tblScore.CourseId),sum(Score)

from tblStudent left Outer join tblScore on tblStudent.StuId=tblScore.StuId

group by tblStudent.StuId,StuName

4、查询姓“李”的老师的个数;

select count(distinct(TeaName))

from tblTeacher

where TeaName like '李%';

5、查询没学过“叶平”老师课的同学的学号、姓名;

select tblStudent.StuId,tblStudent.StuName

from tblStudent

where StuId not in (select distinct( tblScore.StuId) from tblScore,tblCourse,tblTeacher where tblScore.CourseId=tblCourse.CourseId and tblTeacher.TeaId=tblCourse.TeaId and tblTeacher.TeaName='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 tblStudent.StuId,tblStudent.StuName from tblStudent,tblScore where tblStudent.StuId=tblScore.StuId and tblScore.CourseId='001'and exists( Select * from tblScore as tblScore_2 where tblScore_2.StuId=tblScore.StuId and tblScore_2.CourseId='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 StuId,StuName

from tblStudent

where StuId in (select StuId from tblScore ,tblCourse ,tblTeacher where tblScore.CourseId=tblCourse.CourseId and tblTeacher.TeaId=tblCourse.TeaId and tblTeacher.TeaName='叶平' group by StuId having count(tblScore.CourseId)=(select count(CourseId) from tblCourse,tblTeacher where tblTeacher.TeaId=tblCourse.TeaId and TeaName='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 StuId,StuName from (select tblStudent.StuId,tblStudent.StuName,Score ,(select Score from tblScore tblScore_2 where tblScore_2.StuId=tblStudent.StuId and tblScore_2.CourseId='002') Score2

from tblStudent,tblScore where tblStudent.StuId=tblScore.StuId and CourseId='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 StuId,StuName

from tblStudent

where StuId not in (select tblStudent.StuId from tblStudent,tblScore where S.StuId=tblScore.StuId and Score>60);

10、查询没有学全所有课的同学的学号、姓名;

select tblStudent.StuId,tblStudent.StuName

from tblStudent,tblScore

where tblStudent.StuId=tblScore.StuId group by tblStudent.StuId,tblStudent.StuName having count(CourseId) <(select count(CourseId) from tblCourse);

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 StuId,StuName from tblStudent,tblScore where tblStudent.StuId=tblScore.StuId and CourseId in select CourseId from tblScore where StuId='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 tblScore.StuId,StuName

from tblStudent,tblScore

where tblStudent.StuId=tblScore.StuId and CourseId in (select CourseId from tblScore where StuId='001');

13、把“tblScore”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 tblScore set Score=(select avg(tblScore_2.Score)

from tblScore tblScore_2

where tblScore_2.CourseId=tblScore.CourseId ) from tblCourse,tblTeacher where tblCourse.CourseId=tblScore.CourseId and tblCourse.TeaId=tblTeacher.TeaId and tblTeacher.TeaName='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 StuId from tblScore where CourseId in (select CourseId from tblScore where StuId='1002')

group by StuId having count(*)=(select count(*) from tblScore where StuId='1002');

15、删除学习“叶平”老师课的tblScore表记录;

Delect tblScore

from tblCourse ,tblTeacher

where tblCourse.CourseId=tblScore.CourseId and tblCourse.TeaId= tblTeacher.TeaId and TeaName='叶平';

16、向tblScore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 tblScore select StuId,'002',(Select avg(Score)

from tblScore where CourseId='002') from tblStudent where StuId not in (Select StuId from tblScore where CourseId='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 StuId as 学生ID

,(SELECT Score FROM tblScore WHERE tblScore.StuId=t.StuId AND CourseId='004') AS 数据库

,(SELECT Score FROM tblScore WHERE tblScore.StuId=t.StuId AND CourseId='001') AS 企业管理

,(SELECT Score FROM tblScore WHERE tblScore.StuId=t.StuId AND CourseId='006') AS 英语

,COUNT(*) AS 有效课程数, AVG(t.Score) AS 平均成绩

FROM tblScore AS t

GROUP BY StuId

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.CourseId As 课程ID,L.Score AS 最高分,R.Score AS 最低分

FROM tblScore L ,tblScore AS R

WHERE L.CourseId = R.CourseId and

L.Score = (SELECT MAX(IL.Score)

FROM tblScore AS IL,tblStudent AS IM

WHERE L.CourseId = IL.CourseId and IM.StuId=IL.StuId

GROUP BY IL.CourseId)

AND

R.Score = (SELECT MIN(IR.Score)

FROM tblScore AS IR

WHERE R.CourseId = IR.CourseId

GROUP BY IR.CourseId

);

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.CourseId AS 课程号,max(tblCourse.CourseName)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 tblScore T,tblCourse

where t.CourseId=tblCourse.CourseId

GROUP BY t.CourseId

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 CourseId ='001' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分

,100 * SUM(CASE WHEN CourseId = '001' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数

,SUM(CASE WHEN CourseId = '002' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分

,100 * SUM(CASE WHEN CourseId = '002' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数

,SUM(CASE WHEN CourseId = '003' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '003' THEN 1 ELSE 0 END) AS UML平均分

,100 * SUM(CASE WHEN CourseId = '003' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '003' THEN 1 ELSE 0 END) AS UML及格百分数

,SUM(CASE WHEN CourseId = '004' THEN Score ELSE 0 END)/SUM(CASE CourseId WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分

,100 * SUM(CASE WHEN CourseId = '004' AND Score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CourseId = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数

FROM tblScore

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.TeaId) AS 教师ID,MAX(Z.TeaName) AS 教师姓名,C.CourseId AS 课程ＩＤ,MAX(C.CourseName) AS 课程名称,AVG(Score) AS 平均成绩

FROM tblScore AS T,tblCourse AS C ,tblTeacher AS Z

where T.CourseId=C.CourseId and C.TeaId=Z.TeaId

GROUP BY C.CourseId

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

tblScore.StuId As 学生学号,

tblStudent.StuName 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 tblStudent,tblScore LEFT JOIN tblScore AS T1

ON tblScore.StuId = T1.StuId AND T1.CourseId = '001'

LEFT JOIN tblScore AS T2

ON tblScore.StuId = T2.StuId AND T2.CourseId = '002'

LEFT JOIN tblScore AS T3

ON tblScore.StuId = T3.StuId AND T3.CourseId = '003'

LEFT JOIN tblScore AS T4

ON tblScore.StuId = T4.StuId AND T4.CourseId = '004'

WHERE tblStudent.StuId=tblScore.StuId 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 tblScore

LEFT JOIN tblScore AS T1

ON tblScore.StuId = T1.StuId AND T1.CourseId = 'k1'

LEFT JOIN tblScore AS T2

ON tblScore.StuId = T2.StuId AND T2.CourseId = 'k2'

LEFT JOIN tblScore AS T3

ON tblScore.StuId = T3.StuId AND T3.CourseId = 'k3'

LEFT JOIN tblScore AS T4

ON tblScore.StuId = T4.StuId AND T4.CourseId = '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 tblScore.CourseId as 课程ID, CourseName 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 tblScore,tblCourse

where tblScore.CourseId=tblCourse.CourseId

GROUP BY tblScore.CourseId,CourseName;

24、查询学生平均成绩及其名次

SELECT 1+(SELECT COUNT( distinct 平均成绩)

FROM (SELECT StuId,AVG(Score) AS 平均成绩

FROM tblScore

GROUP BY StuId

) AS T1

WHERE 平均成绩 > T2.平均成绩) as 名次,

StuId as 学生学号,平均成绩

FROM (SELECT StuId,AVG(Score) 平均成绩

FROM tblScore

GROUP BY StuId

) 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.StuId as 学生ID,t1.CourseId as 课程ID,Score as 分数

FROM tblScore t1

WHERE Score IN (SELECT TOP 3 Score

FROM tblScore

WHERE t1.CourseId= CourseId

ORDER BY Score DESC

)

ORDER BY t1.CourseId;

26、查询每门课程被选修的学生数

select CourseId,count(StuId) from tblScore group by CourseId;

27、查询出只选修了一门课程的全部学生的学号和姓名

select tblScore.StuId,tblStudent.StuName,count(CourseId) AS 选课数

from tblScore ,tblStudent

where tblScore.StuId=tblStudent.StuId group by tblScore.StuId ,tblStudent.StuName having count(CourseId)=1;

28、查询男生、女生人数

Select count(StuSex) as 男生人数 from tblStudent group by StuSex having StuSex='男';

Select count(StuSex) as 女生人数 from tblStudent group by StuSex having StuSex='女';

29、查询姓“张”的学生名单

SELECT StuName FROM tblStudent WHERE StuName like '张%';

30、查询同名同性学生名单，并统计同名人数

select StuName,count(*) from tblStudent group by StuName having count(*)>1;;

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

select StuName, CONVERT(char (11),DATEPART(year,StuAge)) as age

from tblStudent

where CONVERT(char(11),DATEPART(year,StuAge))='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 CourseId,Avg(Score) from tblScore group by CourseId order by Avg(Score),CourseId 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 StuName,tblScore.StuId ,avg(Score)

from tblStudent,tblScore

where tblStudent.StuId=tblScore.StuId group by tblScore.StuId,StuName 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 StuName,isnull(Score,0)

from tblStudent,tblScore,tblCourse

where tblScore.StuId=tblStudent.StuId and tblScore.CourseId=tblCourse.CourseId and tblCourse.CourseName='数据库'and Score <60;

35、查询所有学生的选课情况;

SELECT tblScore.StuId,tblScore.CourseId,StuName,CourseName

FROM tblScore,tblStudent,tblCourse

where tblScore.StuId=tblStudent.StuId and tblScore.CourseId=tblCourse.CourseId ;

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 tblStudent.StuId,tblStudent.StuName,tblScore.CourseId,tblScore.Score

FROM tblStudent,tblScore

WHERE tblScore.Score>=70 AND tblScore.StuId=tblStudent.StuId;

37、查询不及格的课程，并按课程号从大到小排列

select CourseId from tblScore where scor e <60 order by CourseId ;

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 tblScore.StuId,tblStudent.StuName from tblScore,tblStudent where tblScore.StuId=tblStudent.StuId and Score>80 and CourseId='003';

39、求选了课程的学生人数

select count(*) from tblScore;

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 tblStudent.StuName,Score

from tblStudent,tblScore,tblCourse C,tblTeacher

where tblStudent.StuId=tblScore.StuId and tblScore.CourseId=C.CourseId and C.TeaId=tblTeacher.TeaId and tblTeacher.TeaName='叶平' and tblScore.Score=(select max(Score)from tblScore where CourseId=C.CourseId );

41、查询各个课程及相应的选修人数

select count(*) from tblScore group by CourseId;

42、查询不同课程成绩相同的学生的学号、课程号、学生成绩

select distinct A.StuId,B.Score from tblScore A ,tblScore B where A.Score=B.Score and A.CourseId <>B.CourseId ;

43、查询每门功成绩最好的前两名

SELECT t1.StuId as 学生ID,t1.CourseId as 课程ID,Score as 分数

FROM tblScore t1

WHERE Score IN (SELECT TOP 2 Score

FROM tblScore

WHERE t1.CourseId= CourseId

ORDER BY Score DESC

)

ORDER BY t1.CourseId;

44、统计每门课程的学生选修人数（超过10人的课程才统计）。要求输出课程号和选修人数，查询结果按人数降序排列，查询结果按人数降序排列，若人数相同，按课程号升序排列

select CourseId as 课程号,count(*) as 人数

from tblScore

group by CourseId

order by count(*) desc,CourseId

45、检索至少选修两门课程的学生学号

select StuId

from tblScore

group by StuId

having count(*) > = 2

46、查询全部学生都选修的课程的课程号和课程名

select CourseId,CourseName

from tblCourse

where CourseId in (select CourseId from tblScore group by CourseId)

47、查询没学过“叶平”老师讲授的任一门课程的学生姓名

select StuName from tblStudent where StuId not in (select StuId from tblCourse,tblTeacher,tblScore where tblCourse.TeaId=tblTeacher.TeaId and tblScore.CourseId=tblCourse.CourseId and TeaName='叶平');

48、查询两门以上不及格课程的同学的学号及其平均成绩

select StuId,avg(isnull(Score,0)) from tblScore where StuId in (select StuId from tblScore where Score <60 group by StuId having count(*)>2)group by StuId;

49、检索“004”课程分数小于60，按分数降序排列的同学学号

select StuId from tblScore where CourseId='004'and Score <60 order by Score desc;

50、删除“002”同学的“001”课程的成绩

delete from tblScore where StuId='001'and CourseId='001';