竞争对手 网站流量,做网站代码保密协议,多用户分销系统开发,wordpress无法将图片上传最近在学习SQL嘛,所以各个地方找题目来练手,毕竟现在能离得开数据库么? 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#xff1a; 1、查询“001”课程比“002”课程成绩高的所有学生的学号#x…最近在学习SQL嘛,所以各个地方找题目来练手,毕竟现在能离得开数据库么? 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.scoreb.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
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#001and 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 score60); 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)FROMSC
WHEREC #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002OOUML 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
SELECTmax(Z.T #) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.C# AS 课程,MAX(C.Cname) AS 课程名称,AVG(Score) AS 平均成绩FROMSC AS T,Course AS C,Teacher AS Z
WHERET.C #C.C# and C.T#Z.T#GROUP BYC.C #ORDER BYAVG( Score ) DESC22、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002UML 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 DISTINCTtop 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
FROMStudent,SCLEFT JOIN SC AS T1 ON SC.S # T1.S# AND T1.C# 001LEFT JOIN SC AS T2 ON SC.S # T2.S# AND T2.C# 002LEFT JOIN SC AS T3 ON SC.S # T3.S# AND T3.C# 003LEFT JOIN SC AS T4 ON SC.S # T4.S# AND T4.C# 004WHEREstudent.S #SC.S# andISNULL( T1.score, 0 ) ISNULL( T2.score, 0 ) ISNULL( T3.score, 0 ) ISNULL( T4.score, 0 ) NOT IN (
SELECT DISTINCTTOP 15 WITH TIES ISNULL( T1.score, 0 ) ISNULL( T2.score, 0 ) ISNULL( T3.score, 0 ) ISNULL( T4.score, 0 ) FROMscLEFT JOIN sc AS T1 ON sc.S # T1.S# AND T1.C# k1LEFT JOIN sc AS T2 ON sc.S # T2.S# AND T2.C# k2LEFT JOIN sc AS T3 ON sc.S # T3.S# AND T3.C# k3LEFT JOIN sc AS T4 ON sc.S # T4.S# AND T4.C# k4ORDER BYISNULL( 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]
SELECTSC.C # as 课程ID, CnameAS 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 -]
FROMSC,Coursewhere SC.C #Course.C#GROUP BYSC.C #,Cname;24、查询学生平均成绩及其名次
SELECT1 ( 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)
SELECTt1.S # as 学生ID,t1.C# as 课程ID,Score as 分数FROMSC t1
WHEREscore 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
SELECTSC.S #,Student.Sname,count(C#) AS 选课数FROMSC,Student
WHERESC.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 Studentgroup 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.score70 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 Score80 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.ScoreB.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#004and score 60 order by score desc; 50、删除“002”同学的“001”课程的成绩
delete from Sc where S#001and C#001;
