經典sql面試題（學生表_課程表_成績表_教師表）

轉載：https://www.cnblogs.com/qixuejia/p/3637735.html 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 ...

轉載：https://www.cnblogs.com/qixuejia/p/3637735.html

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) 
  )

插入測試數據語句

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

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 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“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# 
                    ); 
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），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