SQL入门经典练习题

建站990 更新时间：2025-06-08 11:47:03

2023年6月21日发(作者：)

SQL⼊门经典练习题下⾯是oracle数据库的语法SQL数据库⾯试题以及答案（50例题）--可执⾏的oracle建表SQL:--学⽣表create table Student(S# varchar2(100) ,Sname varchar2(100),Sage int,Ssex varchar2(100));comment on table Student is '学⽣表';comment on column Student.S# is '学号';comment on column is '学⽣姓名';comment on column is '学⽣年龄';comment on column is '学⽣性别';--课程表create table Course(C# varchar2(100) ,Cname varchar2(100) ,T# varchar2(100)

);comment on table Course is '课程表';comment on column Course.C# is '课程编号';comment on column is '课程名称';comment on column Course.T# is '教师编号';--成绩表create table SC(S# varchar2(100) ,C# varchar2(100) ,score number);comment on table SC is '成绩表';comment on column SC.S# is '学号';comment on column SC.C# is '课程编号';comment on column is '成绩';--教师表create table Teacher(T# varchar2(100) ,Tname varchar2(100)

);comment on table Teacher is '成绩表';comment on column Teacher.T# is '教师编号';comment on column is '教师名字';个⼈评价：这50套题很经典，都是⼀些常⽤的查询语句。有利于锻炼思维，理解关系数据库表数据如下：--数据插⼊脚本--Course-------------------------------insert into Course (C#, CNAME, T#)values ('001', '语⽂', 'T001');insert into Course (C#, CNAME, T#)values ('002', '数学', 'T002');insert into Course (C#, CNAME, T#)values ('003', '数据库', 'T003');--SC-------------------------------insert into SC (S#, C#, SCORE)values ('1001', '001', 89);insert into SC (S#, C#, SCORE)values ('1001', '002', 92);insert into SC (S#, C#, SCORE)values ('1002', '003', 78);insert into SC (S#, C#, SCORE)values ('1003', '002', 87);--Student---------------------------insert into Student (S#, SNAME, SAGE, SSEX)values ('1001', '王三', 18, 'M');insert into Student (S#, SNAME, SAGE, SSEX)values ('1002', '李四', 19, 'F');insert into Student (S#, SNAME, SAGE, SSEX)values ('1003', '亦⼀', 17, 'M');--Teacher------------------------insert into Teacher (T#, TNAME)values ('T001', '王平');insert into Teacher (T#, TNAME)values ('T002', '孙仲谋');insert into Teacher (T#, TNAME)values ('T003', '叶平');-------------------------------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 > 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)>603、查询所有同学的学号、姓名、选课数、总成绩select student.S_id, , count(sc.C_id), sum(score) from student

left join SC on student.S_id = SC.S_id group by Student.S_id, Sname4、查询姓‘李’的⽼师的个数：select count(distinct(Tname))

from teacher

where tname like '李%';5、查询没有学过“叶平”⽼师可的同学的学号、姓名：select student.S#,

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 ='叶平');6、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 ='叶平' group by S#

having count(SC.C#)=(select count(C#) from Course,Teacher

where Teacher.T#=Course.T# and Tname='叶平'));7、查询学过“011”并且也学过编号“002”课程的同学的学号、姓名：select Student.S#,

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');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#,,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#,

from student, scwhere student.s#=sc.s#

group by student.s#,

having count(c#)<(select count(c#) from course);11、查询⾄少有⼀门课与学号为“1001”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(s2_Score) From sc s2 Where s2.c#=sc.c#)

Where c# IN(Select c# From sc cs INNER JOIN Teacher tc ON cs.t#=tc.t# WHERE 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'); 这个写法是有问题的，如果“1002”同学的学习课程是其它同学的⼦集，那么也会筛选出来；正确写法如下：⼦集且记录数相同select t1.s_id from

(select s_id,count(distinct c_id) as cnt1 from sc where c_id in(select c_id from sc where s_id=2) and s_id <> 2 group by s_id

having count(distinct c_id)=(select count(distinct c_id) from sc where s_id=2)) t1,(select s_id,count(distinct c_id) as cnt2 from sc group by s_id) t2where t1.s_id=t2.s_id and 1=2

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、002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_id as 学⽣ID,(select score from sc where sc.s_id=t.s_id and c_id=1) as 数据库,(select score from sc where sc.s_id=t.s_id and c_id=2) as 企业管理,(select score from sc where sc.s_id=t.s_id and c_id=3) as 英语,count(*) as 有效课程数, avg() as 平均成绩,rank() over(order by avg() desc) as 名次from sc tgroup by s_id

order by avg() asc此题很经典，没做出来。rank over() ⾥⾯是是计算名次的排序；order by是记录展⽰的排序18、查询各科成绩最⾼和最低的分：以如下的形式显⽰：课程ID，最⾼分，最低分select L.c# as 课程ID, as 最⾼分, as 最低分from sc L, sc R

where L.c# = R.c#

and = (select max()

from sc IL, student as IM

where L.c#=IL.c# and IM.s#=IL.s# group by IL.c#)and = (select min() from sc as IR where R.c#=IR.c# group by IR.c#);select c_id,max(score),min(score) from sc group by c_Id;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()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

select c_id 课程编号,round(avg(score),2) 平均分,round(sum(case when score>59 then 1 else 0 end)/count(1)*100.00,2)||'%' 及格率 from scgroup by c_id order by 平均分 asc,及格率 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）：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() AS 教师姓名, C.C# AS 课程ID, 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) 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(002)，UML(003)，数据库(004)：23、统计下列各科成绩，各分数段⼈数：课程ID，课程名称，[100-85],[85-70],[70-60],[ ⼩于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;select c_id 课程ID, (select cname from course t1 where t1.c_id=t2.c_id) 课程名称, count(distinct case when score between 85 and 100 then s_id end ) "[85-100分]⼈数", count(distinct case when score between 70 and 85 then s_id end ) "[75-85分]⼈数", count(distinct case when score between 60 and 70 then s_id end ) "[60-70]⼈数", count(distinct case when score <60 then s_id end ) "⼩于60分⼈数" from sc t2 group by c_id ;注：这种写法更好⼀点，可以排除，同⼈同科⽬错误录⼊了两条记录的情况；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;

select s_id 学号,avg(score) 平均成绩,rank() over(order by avg(score) desc) 名次 from sc group by s_id;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)

select s_id,c_id,dense_rank() over(partition by c_id order by score desc) rank from sc;

注：oracle没有top N的写法；

26、查询每门课程被选修的学⽣数：select c#, count(s#)

from sc

group by c#;27、查询出只选修⼀门课程的全部学⽣的学号和姓名：select t2.s_Id, from student t2 where t2.s_id

in(select s_Id from sc group by sc.s_id having count(distinct sc.c_id)=1);select t1.s_id, from sc t1,student t2 where t1.s_id=t2.s_id

group by t1.s_id, having count(distinct t1.c_id)=1 注：写法2 可加深对group by的理解，实际根据t1.s_id已经能够唯⼀定位，加上完全是语法需要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';select (case when ssex='M' then '男' else '⼥' end) 性别,count(1) ⼈数 from student group by ssex;注：注意单引号，数据库⾥只识别单引号。29、查询姓“张”的学⽣名单：select sname

from student

where sname like '张%';30、查询同名同姓的学⽣名单，并统计同名⼈数：select sanme,count(*)

from student

group by sname

havang 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 agefrom student

where convert(char(11),DATEPART(year,Sage))='1981';32、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;33、查询每门课程的平均成绩，结果按平均成绩升序排序，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;34、查询课程名称为“数据库”，且分数低于60的学⽣名字和分数：select sname, isnull(score,0)

from student, sc ,course

where sc.s#=student.s# and sc.c#=course.c# and ='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#,,sc.c#,

from student,sc

where >=70 and sc.s#=student.s#;37、查询课程和不及格⼈数，并按课程号从⼤到⼩的排列：select c#

from sc

where score<60

order by c#;select c_id , count(1) from sc where score < 60 group by c_id order by c_id;注：很好的考察了对group by ⽤法的理解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#,

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;select count(distinct c_id) from sc where score is not null;注：感觉这样更严谨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 ,score

from student,sc,course c, teacher

where student.s#=sc.S# and sc.c#=c.c#and c.T#=teacher.T#and ='叶平'

and =(select max(score) from sc where c#=c.c#);select 姓名, 成绩 from sc t3,student t4 where t3.s_id=t4.s_id and =(select max(score) from sc

where c_id in(select t1.c_id from course t1,teacher t2 where t1.t_id=t2.t_id and ='叶平'));注：连接4张表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和学号、课程号、学⽣成绩：select distinct a.s#,

from sc a ,sc b

where =

and a.c#<>b.c#;select t1.* from

sc t1,sc t2 where

= and t1.s_id<>t2.s_id and t1.c_id<>t2.c_id order by ;注：使⽤⾃连接的例⼦43、查询每门课程成绩最好的前两名：select t1.s# as 学⽣ID,t1.c# 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#;select (select cname from course where c_id=t1.c_id) 课程名, 学⽣姓名, 排名 from

(select c_id,s_id,rank() over(partition by c_id order by score desc) rank from sc) t1,student t2

where t1.s_id=t2.s_id and <3

注：partition by 以前没⽤过，注意下⽤法；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序，若⼈数相同，按课程号升序排序：select c_id,count(distinct s_id) from sc group by c_id

having count(distinct s_id)>10 order by count(distinct s_id) desc,c_id asc;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、查询全部学⽣选修的课程和课程号和课程名：select c# ,cnamefrom 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');select distinct t3.s_id, from student t3,sc t4 where t3.s_id=t4.s_id and t4.c_id

not in(select t1.c_id from course t1,teacher t2 where t1.t_id=t2.t_id and ='叶平');注：此题集合的思想，1、学过叶平的课的学⽣；2、叶平教过的课取相反数48、查询两门以上不及格课程的同学的学号以及其平均成绩：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#;select s_id,avg(score) from sc group by s_id

having count(distinct case when score < 60 then c_id end)>249、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：delect from sc

where s#='002'

and c#='001';

2023年6月21日发(作者：)

SQL⼊门经典练习题下⾯是oracle数据库的语法SQL数据库⾯试题以及答案（50例题）--可执⾏的oracle建表SQL:--学⽣表create table Student(S# varchar2(100) ,Sname varchar2(100),Sage int,Ssex varchar2(100));comment on table Student is '学⽣表';comment on column Student.S# is '学号';comment on column is '学⽣姓名';comment on column is '学⽣年龄';comment on column is '学⽣性别';--课程表create table Course(C# varchar2(100) ,Cname varchar2(100) ,T# varchar2(100)

);comment on table Course is '课程表';comment on column Course.C# is '课程编号';comment on column is '课程名称';comment on column Course.T# is '教师编号';--成绩表create table SC(S# varchar2(100) ,C# varchar2(100) ,score number);comment on table SC is '成绩表';comment on column SC.S# is '学号';comment on column SC.C# is '课程编号';comment on column is '成绩';--教师表create table Teacher(T# varchar2(100) ,Tname varchar2(100)

);comment on table Teacher is '成绩表';comment on column Teacher.T# is '教师编号';comment on column is '教师名字';个⼈评价：这50套题很经典，都是⼀些常⽤的查询语句。有利于锻炼思维，理解关系数据库表数据如下：--数据插⼊脚本--Course-------------------------------insert into Course (C#, CNAME, T#)values ('001', '语⽂', 'T001');insert into Course (C#, CNAME, T#)values ('002', '数学', 'T002');insert into Course (C#, CNAME, T#)values ('003', '数据库', 'T003');--SC-------------------------------insert into SC (S#, C#, SCORE)values ('1001', '001', 89);insert into SC (S#, C#, SCORE)values ('1001', '002', 92);insert into SC (S#, C#, SCORE)values ('1002', '003', 78);insert into SC (S#, C#, SCORE)values ('1003', '002', 87);--Student---------------------------insert into Student (S#, SNAME, SAGE, SSEX)values ('1001', '王三', 18, 'M');insert into Student (S#, SNAME, SAGE, SSEX)values ('1002', '李四', 19, 'F');insert into Student (S#, SNAME, SAGE, SSEX)values ('1003', '亦⼀', 17, 'M');--Teacher------------------------insert into Teacher (T#, TNAME)values ('T001', '王平');insert into Teacher (T#, TNAME)values ('T002', '孙仲谋');insert into Teacher (T#, TNAME)values ('T003', '叶平');-------------------------------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 > 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)>603、查询所有同学的学号、姓名、选课数、总成绩select student.S_id, , count(sc.C_id), sum(score) from student

left join SC on student.S_id = SC.S_id group by Student.S_id, Sname4、查询姓‘李’的⽼师的个数：select count(distinct(Tname))

from teacher

where tname like '李%';5、查询没有学过“叶平”⽼师可的同学的学号、姓名：select student.S#,

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 ='叶平');6、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 ='叶平' group by S#

having count(SC.C#)=(select count(C#) from Course,Teacher

where Teacher.T#=Course.T# and Tname='叶平'));7、查询学过“011”并且也学过编号“002”课程的同学的学号、姓名：select Student.S#,

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');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#,,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#,

from student, scwhere student.s#=sc.s#

group by student.s#,

having count(c#)<(select count(c#) from course);11、查询⾄少有⼀门课与学号为“1001”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(s2_Score) From sc s2 Where s2.c#=sc.c#)

Where c# IN(Select c# From sc cs INNER JOIN Teacher tc ON cs.t#=tc.t# WHERE 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'); 这个写法是有问题的，如果“1002”同学的学习课程是其它同学的⼦集，那么也会筛选出来；正确写法如下：⼦集且记录数相同select t1.s_id from

(select s_id,count(distinct c_id) as cnt1 from sc where c_id in(select c_id from sc where s_id=2) and s_id <> 2 group by s_id

having count(distinct c_id)=(select count(distinct c_id) from sc where s_id=2)) t1,(select s_id,count(distinct c_id) as cnt2 from sc group by s_id) t2where t1.s_id=t2.s_id and 1=2

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、002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_id as 学⽣ID,(select score from sc where sc.s_id=t.s_id and c_id=1) as 数据库,(select score from sc where sc.s_id=t.s_id and c_id=2) as 企业管理,(select score from sc where sc.s_id=t.s_id and c_id=3) as 英语,count(*) as 有效课程数, avg() as 平均成绩,rank() over(order by avg() desc) as 名次from sc tgroup by s_id

order by avg() asc此题很经典，没做出来。rank over() ⾥⾯是是计算名次的排序；order by是记录展⽰的排序18、查询各科成绩最⾼和最低的分：以如下的形式显⽰：课程ID，最⾼分，最低分select L.c# as 课程ID, as 最⾼分, as 最低分from sc L, sc R

where L.c# = R.c#

and = (select max()

from sc IL, student as IM

where L.c#=IL.c# and IM.s#=IL.s# group by IL.c#)and = (select min() from sc as IR where R.c#=IR.c# group by IR.c#);select c_id,max(score),min(score) from sc group by c_Id;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()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

select c_id 课程编号,round(avg(score),2) 平均分,round(sum(case when score>59 then 1 else 0 end)/count(1)*100.00,2)||'%' 及格率 from scgroup by c_id order by 平均分 asc,及格率 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）：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() AS 教师姓名, C.C# AS 课程ID, 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) 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(002)，UML(003)，数据库(004)：23、统计下列各科成绩，各分数段⼈数：课程ID，课程名称，[100-85],[85-70],[70-60],[ ⼩于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;select c_id 课程ID, (select cname from course t1 where t1.c_id=t2.c_id) 课程名称, count(distinct case when score between 85 and 100 then s_id end ) "[85-100分]⼈数", count(distinct case when score between 70 and 85 then s_id end ) "[75-85分]⼈数", count(distinct case when score between 60 and 70 then s_id end ) "[60-70]⼈数", count(distinct case when score <60 then s_id end ) "⼩于60分⼈数" from sc t2 group by c_id ;注：这种写法更好⼀点，可以排除，同⼈同科⽬错误录⼊了两条记录的情况；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;

select s_id 学号,avg(score) 平均成绩,rank() over(order by avg(score) desc) 名次 from sc group by s_id;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)

select s_id,c_id,dense_rank() over(partition by c_id order by score desc) rank from sc;

注：oracle没有top N的写法；

26、查询每门课程被选修的学⽣数：select c#, count(s#)

from sc

group by c#;27、查询出只选修⼀门课程的全部学⽣的学号和姓名：select t2.s_Id, from student t2 where t2.s_id

in(select s_Id from sc group by sc.s_id having count(distinct sc.c_id)=1);select t1.s_id, from sc t1,student t2 where t1.s_id=t2.s_id

group by t1.s_id, having count(distinct t1.c_id)=1 注：写法2 可加深对group by的理解，实际根据t1.s_id已经能够唯⼀定位，加上完全是语法需要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';select (case when ssex='M' then '男' else '⼥' end) 性别,count(1) ⼈数 from student group by ssex;注：注意单引号，数据库⾥只识别单引号。29、查询姓“张”的学⽣名单：select sname

from student

where sname like '张%';30、查询同名同姓的学⽣名单，并统计同名⼈数：select sanme,count(*)

from student

group by sname

havang 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 agefrom student

where convert(char(11),DATEPART(year,Sage))='1981';32、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;33、查询每门课程的平均成绩，结果按平均成绩升序排序，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;34、查询课程名称为“数据库”，且分数低于60的学⽣名字和分数：select sname, isnull(score,0)

from student, sc ,course

where sc.s#=student.s# and sc.c#=course.c# and ='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#,,sc.c#,

from student,sc

where >=70 and sc.s#=student.s#;37、查询课程和不及格⼈数，并按课程号从⼤到⼩的排列：select c#

from sc

where score<60

order by c#;select c_id , count(1) from sc where score < 60 group by c_id order by c_id;注：很好的考察了对group by ⽤法的理解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#,

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;select count(distinct c_id) from sc where score is not null;注：感觉这样更严谨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 ,score

from student,sc,course c, teacher

where student.s#=sc.S# and sc.c#=c.c#and c.T#=teacher.T#and ='叶平'

and =(select max(score) from sc where c#=c.c#);select 姓名, 成绩 from sc t3,student t4 where t3.s_id=t4.s_id and =(select max(score) from sc

where c_id in(select t1.c_id from course t1,teacher t2 where t1.t_id=t2.t_id and ='叶平'));注：连接4张表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和学号、课程号、学⽣成绩：select distinct a.s#,

from sc a ,sc b

where =

and a.c#<>b.c#;select t1.* from

sc t1,sc t2 where

= and t1.s_id<>t2.s_id and t1.c_id<>t2.c_id order by ;注：使⽤⾃连接的例⼦43、查询每门课程成绩最好的前两名：select t1.s# as 学⽣ID,t1.c# 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#;select (select cname from course where c_id=t1.c_id) 课程名, 学⽣姓名, 排名 from

(select c_id,s_id,rank() over(partition by c_id order by score desc) rank from sc) t1,student t2

where t1.s_id=t2.s_id and <3

注：partition by 以前没⽤过，注意下⽤法；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序，若⼈数相同，按课程号升序排序：select c_id,count(distinct s_id) from sc group by c_id

having count(distinct s_id)>10 order by count(distinct s_id) desc,c_id asc;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、查询全部学⽣选修的课程和课程号和课程名：select c# ,cnamefrom 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');select distinct t3.s_id, from student t3,sc t4 where t3.s_id=t4.s_id and t4.c_id

not in(select t1.c_id from course t1,teacher t2 where t1.t_id=t2.t_id and ='叶平');注：此题集合的思想，1、学过叶平的课的学⽣；2、叶平教过的课取相反数48、查询两门以上不及格课程的同学的学号以及其平均成绩：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#;select s_id,avg(score) from sc group by s_id

having count(distinct case when score < 60 then c_id end)>249、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：delect from sc

where s#='002'

and c#='001';

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