數據庫SQL基本功練習

表架構

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

建表語句 

CREATE TABLE student 
  ( 
     s#    INT, 
     sname nvarchar(32), 
     sage  INT, 
     ssex  nvarchar(8) 
  ) 
CREATE TABLE course 
  ( 
     c#    INT, 
     cname nvarchar(32), 
     t#    INT 
  ) 
CREATE TABLE sc 
  ( 
     s#    INT, 
     c#    INT, 
     score INT 
  ) 
CREATE TABLE teacher 
  ( 
     t#    INT, 
     tname nvarchar(16) 
  )

測試數據

insert into Student select 1,N'劉一',18,N'男' union all
 select 2,N'錢二',19,N'女' union all
 select 3,N'張三',17,N'男' union all
 select 4,N'李四',18,N'女' union all
 select 5,N'王五',17,N'男' union all
 select 6,N'趙六',19,N'女' 
 
 insert into Teacher select 1,N'葉平' union all
 select 2,N'賀高' union all
 select 3,N'楊艷' union all
 select 4,N'周磊'
 
 insert into Course select 1,N'語文',1 union all
 select 2,N'數學',2 union all
 select 3,N'英語',3 union all
 select 4,N'物理',4
 
 insert into SC 
 select 1,1,56 union all 
 select 1,2,78 union all 
 select 1,3,67 union all 
 select 1,4,58 union all 
 select 2,1,79 union all 
 select 2,2,81 union all 
 select 2,3,92 union all 
 select 2,4,68 union all 
 select 3,1,91 union all 
 select 3,2,47 union all 
 select 3,3,88 union all 
 select 3,4,56 union all 
 select 4,2,88 union all 
 select 4,3,90 union all 
 select 4,4,93 union all 
 select 5,1,46 union all 
 select 5,3,78 union all 
 select 5,4,53 union all 
 select 6,1,35 union all 
 select 6,2,68 union all 
 select 6,4,71

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、查詢平均成績大于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”并且也學過編號“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于60分的同學的學號、姓名； 
  select S#,Sname 
  from Student 
  where S# not in (select S.S# from Student AS S,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 distinct S#,Sname from Student,SC where Student.S#=SC.S# and SC.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“數據庫”、“企業管理”、“英語”三門的課程成績，按如下形式顯示： 學生ID,,數據庫,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 數據庫 
        ,(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# 
                    ); 
自己寫的:select c# ,max(score)as 最高分 ,min(score) as 最低分 from dbo.sc  group by 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），數據庫（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 數據庫平均分 
        ,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 數據庫及格百分數 
  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），數據庫（004） 
    [學生ID],[學生姓名],企業管理,馬克思,UML,數據庫,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 數據庫, 
      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:(不考慮成績并列情況) 
      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，并統計同名人數 
  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列的類型是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、查詢平均成績大于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“數據庫”，且分數低于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='數據庫'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，并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”課程分數小于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';