50个常用sql语句网上流行的学生选课表的例子

谁借莪１个温暖的怀抱￠ 2022-06-06 06:25 184阅读 0赞

50个常用sql语句   
  
Student(S\#,Sname,Sage,Ssex) 学生表   
Course(C\#,Cname,T\#) 课程表   
SC(S\#,C\#,score) 成绩表

Teacher(T\#,Tname) 教师表

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.S\# from (select s\#,score from SC where C\#='001') a,(select s\#,score   
from SC where C\#='002') b   
where a.score>b.score and a.s\#=b.s\#;   
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 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 Student.S\#,Student.Sname,count(SC.C\#),sum(score)   
from Student left Outer join SC on Student.S\#=SC.S\#   
group by Student.S\#,Sname   
4、查询姓“李”的老师的个数;   
select count(distinct(Tname))   
from 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 S.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;   
Delect 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&UM

L （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 scor e <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 where C\#=C.C\# );   
41、查询各个课程及相应的选修人数   
select count(\*) from sc group by C\#;   
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.S\#,B.score from SC A ,SC B where A.Score=B.Score and A.C\# <>B.C\# ;   
43、查询每门功成绩最好的前两名   
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 2 score   
FROM SC   
WHERE t1.C\#= C\#   
ORDER BY score DESC   
)   
ORDER BY t1.C\#;   
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 C\# as 课程号,count(\*) as 人数   
from sc

group by C\#   
order by count(\*) desc,c\#   
45、检索至少选修两门课程的学生学号   
select S\#   
from sc   
group by s\#   
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 C\#,Cname   
from Course   
where C\# in (select c\# from sc group by c\#)   
47、查询没学过“叶平”老师讲授的任一门课程的学生姓名   
select Sname from Student where S\# not in (select S\# from Course,Teacher,SC where Course.T\#=Teacher.T\# and SC.C\#=course.C\# and Tname='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 S\#,avg(isnull(score,0)) from SC where S\# in (select S\# from SC where score <60 group by S\# having count(\*)>2)group by S\#;   
49、检索“004”课程分数小于60，按分数降序排列的同学学号   
select S\# from SC where C\#='004'and score <60 order by score desc;   
50、删除“002”同学的“001”课程的成绩   
delete from Sc where S\#='001'and C\#='001';

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