Student(S#,Sname,Sage,Ssex) 學(xué)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(xué)生的學(xué)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(xué)的學(xué)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(xué)的學(xué)號、姓名、選課數(shù)、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(shù)；
select count(distinct(Tname))
from Teacher
where Tname like ‘李%’;
5、查詢沒學(xué)過“葉平”老師課的同學(xué)的學(xué)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(xué)過“001”并且也學(xué)過編號“002”課程的同學(xué)的學(xué)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(xué)過“葉平”老師所教的所有課的同學(xué)的學(xué)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、查詢所有課程成績小于60分的同學(xué)的學(xué)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);
9、查詢沒有學(xué)全所有課的同學(xué)的學(xué)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);
10、查詢至少有一門課與學(xué)號為“1001”的同學(xué)所學(xué)相同的同學(xué)的學(xué)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'）;
11、刪除學(xué)習(xí)“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';
12、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# 課程ID,L.score 最高分,R.score 最低分
FROM SC L ,SC R
WHERE L.C# = R.C#
and
L.score = (SELECT MAX(IL.score)
FROM SC IL,Student IM
WHERE IL.C# = L.C# and IM.S#=IL.S#
GROUP BY IL.C#)
and
R.Score = (SELECT MIN(IR.score)
FROM SC IR
WHERE IR.C# = R.C#
GROUP BY IR.C# );
13、查詢學(xué)生平均成績及其名次
SELECT 1+(SELECT COUNT( distinct 平均成績)
FROM (SELECT S#,AVG(score) 平均成績
FROM SC
GROUP BY S# ) T1
WHERE 平均成績 > T2.平均成績) 名次, S# 學(xué)生學(xué)號,平均成績
FROM (SELECT S#,AVG(score) 平均成績 FROM SC GROUP BY S# ) T2
ORDER BY 平均成績 desc;
14、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(xué)生ID,t1.C# as 課程ID,Score as 分?jǐn)?shù)
FROM SC t1
WHERE score IN (SELECT TOP 3 score
FROM SC
WHERE t1.C#= C#
ORDER BY score DESC)
ORDER BY t1.C#;
15、查詢每門功成績最好的前兩名
SELECT t1.S# as 學(xué)生ID,t1.C# as 課程ID,Score as 分?jǐn)?shù)
FROM SC t1
WHERE score IN (SELECT TOP 2 score
FROM SC
WHERE t1.C#= C#
ORDER BY score DESC )
ORDER BY t1.C#;
補充：
已經(jīng)知道原表
year salary
——————
2000 1000
2001 2000
2002 3000
2003 4000
解：
select b.year,sum(a.salary)
from salary a,salary b
where a.year<=b.year
group by b.year
order by b.year;
在面試過程中多次碰到一道SQL查詢的題目，查詢A(ID,Name)表中第31至40條記錄，ID作為主鍵可能是不是連續(xù)增長的列，完整的查詢語句如下：
方法一：
select top 10 *
from A
where ID >(select max(ID) from (select top 30 ID from A order by ID ) T) order by ID
方法二：
select top 10 *
from A
where ID not In (select top 30 ID from A order by ID)
order by ID