经典面试题sql基础篇-50常用的sql语句(有部分错误）

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#;


select a.S#
	from SC a ,SC b
	where a.S#=b.S#
	and a.C#='001'
	and b.C#='002'
	and a.score>b.score

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;

 SELECT * FROM STUDENT A 
WHERE EXISTS 
(SELECT B.S# FROM SC B,SC C 
WHERE B.C#='111'
AND C.C#='112' 
AND B.SCORE>C.SCORE
AND B.S# = C.S# 
AND A.S# = B.S#
AND A.S# = C.S#)

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';

DELETE FROM SC A WHERE EXISTS ( SELECT 1 FROM TEACHER B,COURSE C WHERE B.T#=C.T# AND B.TNAME ='刘备' AND A.C# = C.C#);
    
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#
                    );

    SELECT MIN(SC.SCORE),MAX(SC.SCORE),SC.C# FROM SC
GROUP BY SC.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），高数（002），OO&UML （003），数据库（004） ps:MKS被河蟹，改高数 
   

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 高数平均分,
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 高数及格百分数,
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），高数（002），UML （003），数据库（004） 
    [学生ID],[学生姓名],企业管理,高数,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 高数,
     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) 
     

Java代码  

　　SELECT * FROM 
　　　　(　　SELECT ROW_NUMBER() OVER (PARTITION BY C# ORDER BY SCORE) AS RN,

　　　　　　SC.*

　　　　　　 FROM SC)
　　　　WHERE RN<=3

    
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';