SQL Server完成50道SQL练习题

要开始用SQL Server了，提前做下题熟悉一下，有些问题可能有简单办法，后面熟悉后再改改

数据表介绍

–1.学生表
Student(SId,Sname,Sage,Ssex)
–SId 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别

create table Student(SId varchar(10),Sname varchar(10),Sage datetime,Ssex varchar(10));
insert into Student values('01' , '赵雷' , '1990-01-01' , '男');
insert into Student values('02' , '钱电' , '1990-12-21' , '男');
insert into Student values('03' , '孙风' , '1990-12-20' , '男');
insert into Student values('04' , '李云' , '1990-12-06' , '男');
insert into Student values('05' , '周梅' , '1991-12-01' , '女');
insert into Student values('06' , '吴兰' , '1992-01-01' , '女');
insert into Student values('07' , '郑竹' , '1989-01-01' , '女');
insert into Student values('09' , '张三' , '2017-12-20' , '女');
insert into Student values('10' , '李四' , '2017-12-25' , '女');
insert into Student values('11' , '李四' , '2012-06-06' , '女');
insert into Student values('12' , '赵六' , '2013-06-13' , '女');
insert into Student values('13' , '孙七' , '2014-06-01' , '女');

–2.课程表
Course(CId,Cname,TId)
–CId 课程编号,Cname 课程名称,TId 教师编号

create table Course(CId varchar(10),Cname nvarchar(10),TId varchar(10));
insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '01');
insert into Course values('03' , '英语' , '03');

–3.教师表
Teacher(TId,Tname)
–TId 教师编号,Tname 教师姓名

create table Teacher(TId varchar(10),Tname varchar(10));
insert into Teacher values('01' , '张三');
insert into Teacher values('02' , '李四');
insert into Teacher values('03' , '王五');

–4.成绩表
SC(SId,CId,score)
–SId 学生编号,CId 课程编号,score 分数

create table SC(SId varchar(10),CId varchar(10),score decimal(18,1));
insert into SC values('01' , '01' , 80);
insert into SC values('01' , '02' , 90);
insert into SC values('01' , '03' , 99);
insert into SC values('02' , '01' , 70);
insert into SC values('02' , '02' , 60);
insert into SC values('02' , '03' , 80);
insert into SC values('03' , '01' , 80);
insert into SC values('03' , '02' , 80);
insert into SC values('03' , '03' , 80);
insert into SC values('04' , '01' , 50);
insert into SC values('04' , '02' , 30);
insert into SC values('04' , '03' , 20);
insert into SC values('05' , '01' , 76);
insert into SC values('05' , '02' , 87);
insert into SC values('06' , '01' , 31);
insert into SC values('06' , '03' , 34);
insert into SC values('07' , '02' , 89);
insert into SC values('07' , '03' , 98);
  1. 查询" 01 “课程比” 02 "课程成绩高的学生的信息及课程分数
select Student.Sname,c.score01,score02
from Student INNER JOIN
(SELECT a.Sid,a.score score01,b.score score02
FROM (SELECT Sid,score FROM sc WHERE cid='01') a ,
	(SELECT sid,score FROM SC where cid='02') b
WHERE a.Sid=b.SId AND a.score>b.score) c
ON Student.sid=c.Sid

1.1 查询同时存在"01"课程和"02"课程的情况

SELECT a.Sid,a.score score01,b.score score02
FROM (SELECT Sid,score FROM sc WHERE cid='01') a ,
	(SELECT sid,score FROM SC where cid='02') b
WHERE a.Sid=b.SId

1.2 查询存在"01"课程但可能不存在"02"课程的情况（不存在时显示为null)

select *
from (select Sid,CId from SC where CId='01') a
    left join (select Sid,CId from SC where CId='02') b
on a.SId=b.SId and a.CId='01'
1.3 查询不存在"01"课程但存在"02"课程的情况
select *
from SC
where SC.Sid  not in (select Sid from SC where cid='01')
    and SC.CId='02'
  1. 查询平均成绩大于等于 60 分的同学的学生编号和学生姓名和平均成绩
select *
from
(select s.Sid,s.Sname ,avg(score) avgscore
from Student S left join SC S2 on S.Sid = S2.SId
group by s.Sid, s.Sname) a
where a.avgscore>60
  1. 查询在 SC 表存在成绩的学生信息
select *
from Student
where Sid in (select distinct Sid
    from SC)
  1. 查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩(没成绩的显示为 null )
select S.Sid 学生编号,S.Sname 学生姓名,count(S2.CId) 选课总数,sum(S2.score) 总成绩
from Student S left join SC S2 on S.Sid = S2.SId
group by S.Sid, S.Sname

4.1 查有成绩的学生信息

select *
from Student
where Sid in (select DISTINCT Sid from SC)
  1. 查询「李」姓老师的数量
select count(TId) 李姓老师数量
from Teacher
where Tname like '李%'
  1. 查询学过「张三」老师授课的同学的信息
select *
from Student
where Sid in (select Sid
    from SC
    where SC.CId in (select Cid
        from Course
        where Course.TId=(select TId from Teacher where Tname='张三')))
  1. 查询没有学全所有课程的同学的信息
select *
from Student
where Sid not in(select Sid
    from SC
    group by Sid
    having count(*)=(select count(Cid) from Course ))
  1. 查询至少有一门课与学号为" 01 "的同学所学相同的同学的信息
select *
from Student
where Sid in (select Sid
    from SC
    where Cid in (select Cid
        from SC where Sid='01'))
  1. 查询和" 01 "号的同学学习的课程 完全相同的其他同学的信息
select *
from Student
where Sid not in (
    select distinct cSid from
        (select c.Sid cSid,Sc.CId scCid
        from
        (select a.Sid,b.Cid
        from Student a,(select Cid from SC where Sid='01') b) c left join sc on c.Sid=sc.Sid and c.Cid=sc.CId) d
        where d.scCid is null
    )
  1. 查询没学过"张三"老师讲授的任一门课程的学生姓名
select Sname
from Student
where Sid not in (
    select Sid
    from SC
    where sc.CId in(
        select Cid
        from Course
        where TId=(
            select Tid from Teacher where Tname='张三'
            )
        )
    )
  1. 查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩
select student.Sid,Student.Sname,avg(score)
from Student,SC
where student.Sid=sc.SId
    and sc.score<60
group by student.Sid, Student.Sname
having count(*)>=2
  1. 检索" 01 "课程分数小于 60，按分数降序排列的学生信息
select Student.*
from SC,Student
where SC.CId='01' and SC.score<60 and SC.SId=Student.Sid
order by SC.score desc
  1. 按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
select sc.Sid,sc.Cid,sc.score,a.avgscore
from SC left join (select SId,avg(score) avgscore
    from SC group by SId) a
    on sc.SId = a.SId
order by a.avgscore desc
  1. 查询各科成绩最高分、最低分和平均分：
    以如下形式显示：课程 ID，课程 name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率
    及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90
    要求输出课程号和选修人数，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 a.Cname 课程,b.*
from Course a,
(select CId 课程ID,max(score) 最高分,min(score) 最低分,avg(score) 平均成绩,count(*) 选课人数,
    convert(varchar,CONVERT(decimal(18, 1),100*sum(CASE WHEN score>=60 THEN 1 ELSE 0 END)/count(*)))+'%' 及格率,
    convert(varchar,CONVERT(decimal(18, 1),100*sum(case when score>=70 and score<80 then 1 else 0 end)/count(*)))+'%' 中等率,
    convert(varchar,CONVERT(decimal(18, 1),100*sum(CASE WHEN score>=80 AND score<90 THEN 1 ELSE 0 END)/count(*)))+'%' 优良率,
    convert(varchar,CONVERT(decimal(18, 1),100*sum(CASE WHEN score>=90 THEN 1 ELSE 0 END)/count(*)))+'%' 优秀率
from SC
group by CId
) b
where a.Cid=b.课程ID
order by b.选课人数 desc,b.课程ID
  1. 按各科成绩进行排序，并显示排名， Score 重复时保留名次空缺
SELECT
    t.CId,
    t.SId,
    t.score,
    ( SELECT COUNT (1) FROM SC WHERE CID = t.CID AND score > t.score )+1 rank 
FROM
    sc t 
ORDER BY
    t.cid ,
    rank

15.1 按各科成绩进行排序，并显示排名， Score 重复时合并名次

SELECT
    t.CId,
    t.SId,
    t.score,
    ( SELECT COUNT ( DISTINCT score ) FROM SC WHERE CID = t.CID AND score >= t.score ) rank 
FROM
    sc t 
ORDER BY
    t.cid ,
    rank

按科目、成绩排序，不重复
PARTITION BY的作用就是根据指定的某个列对结果集先进行分组，再排名

select *,row_number() over (partition by Cid order by score desc) as rank
from sc
order by CId
  1. 查询学生的总成绩，并进行排名，总分重复时保留名次空缺
SELECT
    *,
    rank ( ) OVER ( ORDER BY totalScore DESC ) 排名 
FROM
    ( SELECT Sid, SUM(score) totalScore FROM SC GROUP BY Sid ) A

16.1 查询学生的总成绩，并进行排名，总分重复时不保留名次空缺

SELECT
    *,
    dense_rank ( ) OVER ( ORDER BY totalScore DESC ) 排名 
FROM
    ( SELECT Sid, SUM(score) totalScore FROM SC GROUP BY Sid ) A
  1. 统计各科成绩各分数段人数：课程编号，课程名称，[100-85]，[85-70]，[70-60]，[60-0] 及所占百分比
select a.Cname 课程,b.*
from Course a,
(select CId 课程ID,count(*) 选课人数,
    convert(varchar,convert(decimal(18, 1),100*sum(case when score>=0  and score<60   then 1 else 0 end)/count(*)))+'%' [0-60],
    convert(varchar,CONVERT(decimal(18, 1),100*sum(case when score>=60 and score<70   then 1 else 0 end)/count(*)))+'%' [60-70],
    convert(varchar,CONVERT(decimal(18, 1),100*sum(CASE WHEN score>=70 and score<85   then 1 else 0 end)/count(*)))+'%' [70-85],
    convert(varchar,CONVERT(decimal(18, 1),100*sum(CASE WHEN score>=85 and score<=100 then 1 else 0 end)/count(*)))+'%' [85-100]
from SC
group by CId
) b
where a.Cid=b.课程ID
order by b.选课人数 desc,b.课程ID
  1. 查询各科成绩前三名的记录
select a.cid,a.sid,a.score 
from sc a
where (select count(*) from sc 
    where a.CId=sc.CId and a.score<sc.score)<3
    order by a.CId,a.score desc
  1. 查询每门课程被选修的学生数
select cid,count(sid)
from SC
group by cid
  1. 查询出只选修两门课程的学生学号和姓名
select sid,Sname
from Student
where SId in (select SId
    from SC
    group by SId
    having count(*)=2)
  1. 查询男生、女生人数
select Ssex,count(*)
from Student
group by Ssex
  1. 查询名字中含有「风」字的学生信息
select *
from Student
where Sname like '%风%'
  1. 查询同名同性学生名单，并统计同名人数
select a.*,b.totalPeople
from Student a left join (select Sname,Ssex,count(*) totalPeople
    from Student
    group by Sname,Ssex
    having 
) b on a.Sname=b.Sname and a.Ssex=b.Ssex
where b.totalPeople>1
  1. 查询 1990 年出生的学生名单
select *
from Student
where DATEPART(year, Sage)='1990'
  1. 查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列
select Cid,AVG(score) 平均成绩
from SC
group by CId
order by AVG(score) desc,CId
  1. 查询平均成绩大于等于 85 的所有学生的学号、姓名和平均成绩
select SC.Sid,Student.Sname,avg(SC.score) avgscore
from SC left join Student on SC.Sid=student.Sid
group by SC.SId,Student.Sname
having AVG(SC.score)>85
  1. 查询课程名称为「数学」，且分数低于 60 的学生姓名和分数
select s.Sname 姓名,sc.score 分数
from sc left join Course c on sc.CId=c.CId
    left join Student s on s.SId=sc.SId
where c.Cname = '数学' and sc.score < 60
  1. 查询所有学生的课程及分数情况（存在学生没成绩，没选课的情况）
select b.Sname,Course.Cname,b.score
from
(select a.SId,a.Sname,sc.cid,sc.score
from 
(select sid,Sname,cid
from Student,Course) a left join sc
    on a.sid=sc.sid and a.cid=sc.cid) b left join Course on b.cid=Course.cid
  1. 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 s.Sname,c.Cname,sc.score
from Student s,Course c,SC
where s.SId=sc.SId and c.CId=sc.CId
    and sc.score>=70
  1. 查询不及格的课程
select DISTINCT Course.Cname
from SC,Course
where sc.CId=Course.CId and sc.score<60
  1. 查询课程编号为 01 且课程成绩在 80 分以上的学生的学号和姓名
select s.sid 学号,s.Sname 姓名
from Student s,SC
where s.SId=sc.SId and sc.score>80 and sc.CId='01'
  1. 求每门课程的学生人数
select Cid 课程编号,COUNT(*) 数量
from SC
group by CId
  1. 成绩不重复，查询选修「李四」老师所授课程的学生中，成绩最高的学生信息及其成绩
select Student.SId,Student.Sname,Student.Sage,Student.Ssex,score
from student, teacher, course,sc 
where teacher.tid = course.tid
and sc.sid = student.sid
and sc.cid = course.cid
and Teacher.tname = '李四'
and score = (select max(score) from (
    select score
    from (
    select Student.SId,Student.Sname,Student.Sage,Student.Ssex,score
    from student, teacher, course,sc 
    where teacher.tid = course.tid
    and sc.sid = student.sid
    and sc.cid = course.cid
    and Teacher.tname = '李四') a
    group by score
    having count(*)=1) a1)
  1. 成绩有重复的情况下，查询选修「李四」老师所授课程的学生中，成绩最高的学生信息及其成绩
SELECT s.*,sc.score
FROM
    Student s,Course c,Teacher t,SC 
WHERE
    s.SId= sc.SId AND c.CId= sc.CId AND t.TId= c.TId and t.Tname='李四'
    and sc.score=(select MAX(score)
        from
            Student s,Course c,Teacher t,SC 
        where
            s.SId= sc.SId AND c.CId= sc.CId AND t.TId= c.TId and t.Tname='李四')
  1. 查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩
select *
from sc
where SId in (
    select a.SId
    from sc a inner join sc b 
        on a.CId<>b.CId and a.score=b.score and a.SId=b.SId)
  1. 查询每门功课成绩最好的前两名
select a.cid,a.sid,a.score
from sc a
where a.sid in (
    select top 2 SId
    from sc b 
    where a.CId=b.CId
    order by b.score desc
    )
order by a.cid,a.score desc
  1. 统计每门课程的学生选修人数（超过 5 人的课程才统计）。
select Course.Cname 课程,count(*) 选修人数
from SC left join Course on sc.cid=Course.CId
group by Course.Cname
having count(*)>5
  1. 检索至少选修两门课程的学生学号
select sid
from SC
group by sid
having count(*)>=2
  1. 查询选修了全部课程的学生信息
select Sname
from sc,Student
where sc.SId=Student.SId
group by Sname
having count(*)>(select count(*) from Course)
  1. 查询各学生的年龄，只按年份来算
SELECT
    SId 学号,
    Sname 姓名,
    YEAR ( GETDATE( ) ) - YEAR ( Sage ) 年龄 
FROM
    Student
  1. 按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一
SELECT
    SId 学号,
    Sname 姓名,
    CASE WHEN GETDATE() < Sage THEN YEAR(GETDATE()) - YEAR(Sage)-1
        ELSE YEAR(GETDATE()) - YEAR(Sage)
    END AS 年龄
FROM
    Student
  1. 查询本周过生日的学生
select sid,Sname
from Student
where DATEPART(week, Sage)=DATEPART(week, GETDATE())
  1. 查询下周过生日的学生
select sid,Sname
from Student
where DATEPART(week, Sage)-DATEPART(week, GETDATE())=1
  1. 查询本月过生日的学生
select sid,Sname
from Student
where DATEPART(month, Sage)=DATEPART(month, GETDATE())
  1. 查询下月过生日的学生
select a.Sname
from (
select sid,Sname,
    CASE WHEN DATEPART(month, GETDATE())=12 THEN 1
    ELSE DATEPART(month, GETDATE())+1
END as nextMonth,DATEPART(month, Sage) birthday
from Student) a
where a.birthday=a.nextMonth
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