经典SQL语句

生成表和数据

create table STUDENT(  SNO varchar2(10) primary key,  NAME varchar2(20),  AGE number(2),  SEX varchar2(5)  );  create table TEACHER(  TNO varchar2(10) primary key,  NAME varchar2(20)  );  create table COURSE(  CNO varchar2(10) primary key,  NAME varchar2(20),  TNO varchar2(20)  );  create table SC(  SNO varchar2(10),  CNO varchar2(10),  SCORE number(4,2));  

初始化学生表的数据

insert into STUDENT values ('s001','张三',23,'男');  insert into STUDENT values ('s002','李四',23,'男');  insert into STUDENT values ('s003','吴鹏',25,'男');  insert into STUDENT values ('s004','琴沁',20,'女');  insert into STUDENT values ('s005','王丽',20,'女');  insert into STUDENT values ('s006','李波',21,'男');  insert into STUDENT values ('s007','刘玉',21,'男');  insert into STUDENT values ('s008','萧蓉',21,'女');  insert into STUDENT values ('s009','陈萧晓',23,'女');  insert into STUDENT values ('s010','陈美',22,'女');  

初始化教师表

insert into TEACHER values ('t001', '刘阳');  insert into TEACHER values ('t002', '谌燕');  insert into TEACHER values ('t003', '胡明星');  

初始化课程表

insert into COURSE values ('c001','J2SE','t002');  insert into COURSE values ('c002','Java Web','t002');  insert into COURSE values ('c003','SSH','t001');  insert into COURSE values ('c004','Oracle','t001');  insert into COURSE values ('c005','SQL SERVER 2005','t003');  insert into COURSE values ('c006','C#','t003');  insert into COURSE values ('c007','JavaScript','t002');  insert into COURSE values ('c008','DIV+CSS','t001');  insert into COURSE values ('c009','PHP','t003');  insert into COURSE values ('c010','EJB3.0','t002');   

初始化成绩表

insert into SC values ('s001','c001',78.9);  insert into SC values ('s002','c001',80.9);  insert into SC values ('s003','c001',81.9);  insert into SC values ('s004','c001',60.9);  insert into SC values ('s001','c002',82.9);  insert into SC values ('s002','c002',72.9);  insert into SC values ('s003','c002',81.9);  insert into SC values ('s001','c003',59);  

执行后生成如下三张表

1、查询“001”课程比“002”课程成绩高的所有学生的学号；  

SELECT a.snoFROM  (SELECT sno,score FROM SC WHERE cno='c001'  ) a,  (SELECT sno,score FROM SC WHERE cno='c002'  ) bWHERE a.score>b.scoreAND a.sno=b.sno;

2、查询平均成绩大于60分的同学的学号和平均成绩；

SELECT sno,AVG(score) FROM sc GROUP BY sno HAVING AVG(score) >60;

3、查询所有同学的学号、姓名、选课数、总成绩；

SELECT s2.sno,  s1.name,  COUNT(*),  SUM(score)FROM STUDENT s1,  SC s2WHERE s1.sno = s2.snoGROUP BY s2.sno,s1.name;

4、查询姓“刘”的老师的个数；

select count(distinct(name))  from TEACHER  where name like '刘%';

5、查询没学过“刘阳”老师课的同学的学号、姓名；

SELECT sno,  nameFROM STUDENT WHERE sno NOT IN  (SELECT DISTINCT( SC.sno)  FROM SC sc,    COURSE c,    TEACHER t  WHERE sc.cno=c.cno  AND t.tno   =c.tno  AND t.name  ='刘阳'  );

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 fromStudent,SC where Student.S#=SC.S# andSC.C#='001'and exists( Select * from SC as SC_2 whereSC_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# andTeacher.T#=Course.T# and Teacher.Tname='叶平'group by S#having count(SC.C#)=(select count(C#) fromCourse,Teacher  whereTeacher.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# andC#='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 sno,  nameFROM StudentWHERE sno NOT IN  (SELECT sc.sno FROM SC sc WHERE score>60  );---或者SELECT sno,  nameFROM StudentWHERE sno  IN  (SELECT s.sno FROM STUDENT s left join sc on s.sno=sc.sno  group by s.sno having nvl(max(score),0)<60  );

10、查询没有学全所有课的同学的学号、姓名；

SELECT sno,  nameFROM STUDENTWHERE sno IN  (SELECT sno  FROM SC  GROUP BY sno  HAVING COUNT(cno)<    (SELECT COUNT(*) 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.sno,  s.nameFROM STUDENT S,  SC scWHERE s.sno =sc.snoAND sc.cno IN  (SELECT cno FROM SC WHERE sno='1001'  );

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 FROM SC WHERE cno IN( SELECT cno FROM SC sc JOIN COURSE c ON sc.cno=c.cno WHERE c.name='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# notin (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 ASIL,Student AS IM

                      WHERE L.C# =IL.C# and IM.S#=IL.S#

                      GROUP BYIL.C#)

        AND

        R.Score= (SELECT MIN(IR.score)

                      FROM SC ASIR

                      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&UML （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 cno,count(sno) from sc group by cno; 

27、查询出只选修了一门课程的全部学生的学号和姓名 
SELECT sno,  nameFROM studentWHERE sno IN  ( SELECT sno FROM SC sc GROUP BY sc.sno HAVING COUNT(cno)=1  );


30、查询同名同性学生名单，并统计同名人数 
<span style="font-weight: normal;">select name,count(*) from Student group by name having  count(*)>1;</span>



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 cno,Avg(score) from SC group by cno order by Avg(score),cno 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 
<span style="font-weight: normal;"><span style="font-size:10px;">SELECT s.sno,  s.name,  scoreFROM STUDENT s,  (SELECT sc.sno,    AVG(score) score  FROM Student s,    SC sc  WHERE s.sno=sc.sno  GROUP BY sc.sno  ) ssWHERE s.sno=ss.sno;</span></span>



35、查询所有学生的选课情况； 
SELECT sc.sno,  sc.cno,  s.sname,  c.nameFROM SC sc,  Student s,  Course cWHERE sc.sno=s.snoAND sc.cno  =c.cno ;




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 * from sc where score <60 order by cno ;


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； 
<span style="font-weight: normal;">SELECT sc.sno,  s.nameFROM SC sc,  STUDENT tWHERE sc.sno=s.snoAND score   >80AND sc.sno  ='003';</span>

39、求选了课程的学生人数   
select count(distinct sc.sno) 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 sno from SC where cno='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 sno='002'and cno='001';