50個常用的sql語句

Student(S#,Sname,Sage,Ssex) 學生表

Course(C#,Cname,T#) 課程表

SC(S#,C#,score) 成績表

Teacher(T#,Tname) 教師表

問題：

1、查詢“001”課程比“002”課程成績高的所有學生的學號；

 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#;

2、查詢平均成績大於60分的同學的學號和平均成績；

    select S#,avg(score)

    from sc

    group by S# having avg(score) >60;

3、查詢所有同學的學號、姓名、選課數、總成績；

 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、查詢姓“李”的老師的個數；

 select count(distinct(Tname))

 from Teacher

 where Tname like '李%';

5、查詢沒學過“葉平”老師課的同學的學號、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='葉平');

6、查詢學過“001”並且也學過編號“002”課程的同學的學號、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、查詢學過“葉平”老師所教的所有課的同學的學號、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='葉平' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='葉平'));

8、查詢課程編號“002”的成績比課程編號“001”課程低的所有同學的學號、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、查詢所有課程成績小於60分的同學的學號、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、查詢沒有學全所有課的同學的學號、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、查詢至少有一門課與學號為“1001”的同學所學相同的同學的學號和姓名；

    select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001';

12、查詢至少學過學號為“001”同學所有一門課的其他同學學號和姓名；

    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“葉平”老師教的課的成績都更改為此課程的平均成績；

    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='葉平');

14、查詢和“1002”號的同學學習的課程完全相同的其他同學學號和姓名；

    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、刪除學習“葉平”老師課的SC表記錄；

    Delect SC

    from course ,Teacher 

    where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='葉平';

16、向SC表中插入一些記錄，這些記錄要求符合以下條件：沒有上過編號“003”課程的同學學號、2、

    號課的平均成績；

    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、按平均成績從高到低顯示所有學生的“資料庫”、“企業管理”、“英語”三門的課程成績，按如下形式顯示： 學生ID,,資料庫,企業管理,英語,有效課程數,有效平均分

    SELECT S# as 學生ID

        ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 資料庫

        ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企業管理

        ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS 英語

        ,COUNT(*) AS 有效課程數, AVG(t.score) AS 平均成績

    FROM SC AS t

    GROUP BY S#

    ORDER BY avg(t.score) 

18、查詢各科成績最高和最低的分：以如下形式顯示：課程ID，最高分，最低分

    SELECT L.C# As 課程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、按各科平均成績從低到高和及格率的百分數從高到低順序

    SELECT t.C# AS 課程號,max(course.Cname)AS 課程名,isnull(AVG(score),0) AS 平均成績

        ,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分數

    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、查詢如下課程平均成績和及格率的百分數(用"1行"顯示): 企業管理（001），馬克思（002），OO&UML （003），資料庫（004）

    SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企業管理平均分

        ,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 企業管理及格百分數

        ,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 馬克思平均分

        ,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 馬克思及格百分數

        ,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及格百分數

        ,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 資料庫平均分

        ,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 資料庫及格百分數

 FROM SC

21、查詢不同老師所教不同課程平均分從高到低顯示

 SELECT max(Z.T#) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.C# AS 課程ＩＤ,MAX(C.Cname) AS 課程名稱,AVG(Score) AS 平均成績

    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、查詢如下課程成績第 3 名到第 6 名的學生成績單：企業管理（001），馬克思（002），UML （003），資料庫（004）

    [學生ID],[學生姓名],企業管理,馬克思,UML,資料庫,平均成績

    SELECT DISTINCT top 3

      SC.S# As 學生學號,

        Student.Sname AS 學生姓名 ,

      T1.score AS 企業管理,

      T2.score AS 馬克思,

      T3.score AS UML,

      T4.score AS 資料庫,

      ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 總分

      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、統計列印各科成績,各分數段人數:課程ID,課程名稱,[100-85],[85-70],[70-60],[ <60]

    SELECT SC.C# as 課程ID, Cname as 課程名稱

        ,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、查詢學生平均成績及其名次

      SELECT 1+(SELECT COUNT( distinct 平均成績)

              FROM (SELECT S#,AVG(score) AS 平均成績

                      FROM SC

                  GROUP BY S#

                  ) AS T1

            WHERE 平均成績 > T2.平均成績) as 名次,

      S# as 學生學號,平均成績

    FROM (SELECT S#,AVG(score) 平均成績

            FROM SC

        GROUP BY S#

        ) AS T2

    ORDER BY 平均成績 desc;

25、查詢各科成績前三名的記錄:(不考慮成績並列情況)

      SELECT t1.S# as 學生ID,t1.C# as 課程ID,Score as 分數

      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、查詢每門課程被選修的學生數

 select c#,count(S#) from sc group by C#;

27、查詢出只選修了一門課程的全部學生的學號和姓名

 select SC.S#,Student.Sname,count(C#) AS 選課數

 from SC ,Student

 where SC.S#=Student.S# group by SC.S# ,Student.Sname having count(C#)=1;

28、查詢男生、女生人數

    Select count(Ssex) as 男生人數 from Student group by Ssex having Ssex='男';

    Select count(Ssex) as 女生人數 from Student group by Ssex having Ssex='女'；

29、查詢姓“張”的學生名單

    SELECT Sname FROM Student WHERE Sname like '張%';

30、查詢同名同性學生名單，並統計同名人數

 select Sname,count(*) from Student group by Sname having count(*)>1;;

31、1981年出生的學生名單(注：Student表中Sage列的型別是datetime)

    select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age

    from student

    where CONVERT(char(11),DATEPART(year,Sage))='1981';

32、查詢每門課程的平均成績，結果按平均成績升序排列，平均成績相同時，按課程號降序排列

    Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;

33、查詢平均成績大於85的所有學生的學號、姓名和平均成績

    select Sname,SC.S# ,avg(score)

    from Student,SC

    where Student.S#=SC.S# group by SC.S#,Sname having    avg(score)>85;

34、查詢課程名稱為“資料庫”，且分數低於60的學生姓名和分數

    Select Sname,isnull(score,0)

    from Student,SC,Course

    where SC.S#=Student.S# and SC.C#=Course.C# and Course.Cname='資料庫'and score <60;

35、查詢所有學生的選課情況；

    SELECT SC.S#,SC.C#,Sname,Cname

    FROM SC,Student,Course

    where SC.S#=Student.S# and SC.C#=Course.C# ;

36、查詢任何一門課程成績在70分以上的姓名、課程名稱和分數；

    SELECT distinct student.S#,student.Sname,SC.C#,SC.score

    FROM student,Sc

    WHERE SC.score>=70 AND SC.S#=student.S#;

37、查詢不及格的課程，並按課程號從大到小排列

    select c# from sc where scor e <60 order by C# ;

38、查詢課程編號為003且課程成績在80分以上的學生的學號和姓名；

    select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#='003';

39、求選了課程的學生人數

    select count(*) from sc;

40、查詢選修“葉平”老師所授課程的學生中，成績最高的學生姓名及其成績

    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='葉平' and SC.score=(select max(score)from SC where C#=C.C# );

41、查詢各個課程及相應的選修人數

    select count(*) from sc group by C#;

42、查詢不同課程成績相同的學生的學號、課程號、學生成績

 select distinct A.S#,B.score from SC A ,SC B where A.Score=B.Score and A.C# <>B.C# ;

43、查詢每門功成績最好的前兩名

    SELECT t1.S# as 學生ID,t1.C# as 課程ID,Score as 分數

      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、統計每門課程的學生選修人數（超過10人的課程才統計）。要求輸出課程號和選修人數，查詢結果按人數降序排列，查詢結果按人數降序排列，若人數相同，按課程號升序排列 

    select C# as 課程號,count(*) as 人數

    from sc 

    group by C#

    order by count(*) desc,c# 

45、檢索至少選修兩門課程的學生學號

    select S# 

    from sc 

    group by s#

    having count(*) > = 2

46、查詢全部學生都選修的課程的課程號和課程名

    select C#,Cname 

    from Course 

    where C# in (select c# from sc group by c#) 

47、查詢沒學過“葉平”老師講授的任一門課程的學生姓名

    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='葉平');

48、查詢兩門以上不及格課程的同學的學號及其平均成績

    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、檢索“004”課程分數小於60，按分數降序排列的同學學號

    select S# from SC where C#='004'and score <60 order by score desc;

50、刪除“002”同學的“001”課程的成績

delete from Sc where S#='001'and C#='001';

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