常見SQL數據庫面試題和答案(一)

Student(S#,Sname,Sage,Ssex) 學生表

S#：學號；Sname：學生姓名；Sage：學生年齡；Ssex：學生性別

Course(C#,Cname,T#) 課程表 C#,課程編號；Cname：課程名字；T#：教師編號

SC(S#,C#,score) 成績表 S#：學號；C#,課程編號；score：成績

Teacher(T#,Tname) 教師表 T#：教師編號； Tname：教師名字

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 S whereC#='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 scgroup 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

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

select Student.S#,Student.Sname from Student,SC

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

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“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#

);

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

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關鍵字: SQL Sage 人生第一份工作