SQL练习题汇总（Sqlserver和Mysql版本）

所需表及数据执行脚本：

CREATE TABLE STUDENT
(SNO VARCHAR(3) NOT NULL,
SNAME VARCHAR(4) NOT NULL,
SSEX VARCHAR(2) NOT NULL,
SBIRTHDAY DATETIME,
CLASS VARCHAR(5))
go
CREATE TABLE COURSE
(CNO VARCHAR(5) NOT NULL,
CNAME VARCHAR(10) NOT NULL,
TNO VARCHAR(10) NOT NULL)
go
CREATE TABLE SCORE
(SNO VARCHAR(3) NOT NULL,
CNO VARCHAR(5) NOT NULL,
DEGREE NUMERIC(10, 1) NOT NULL)
go
CREATE TABLE TEACHER
(TNO VARCHAR(3) NOT NULL,
TNAME VARCHAR(4) NOT NULL, TSEX VARCHAR(2) NOT NULL,
TBIRTHDAY DATETIME NOT NULL, PROF VARCHAR(6),
DEPART VARCHAR(10) NOT NULL)
go
CREATE TABLE [GRADE](
    [low] [numeric](3, 0) NULL,
    [up] [numeric](3, 0) NULL,
    [rank] [char](1) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (108 ,'曾华'
,'男' ,1977-09-01,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (105 ,'匡明'
,'男' ,1975-10-02,95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (107 ,'王丽'
,'女' ,1976-01-23,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李军'
,'男' ,1976-02-20,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (109 ,'王芳'
,'女' ,1975-02-10,95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (103 ,'陆君'
,'男' ,1974-06-03,95031);
GO
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-105' ,'计算机导论',825)
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-245' ,'操作系统' ,804);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('6-166' ,'数据电路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,100);
GO
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-245',86);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-245',75);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-245',68);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-105',92);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-105',88);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-105',76);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'3-105',64);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'3-105',91);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'3-105',78);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'6-166',85);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'6-106',79);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);
GO
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');
GO
INSERT INTO [GRADE]([low],[up],[rank]) VALUES(90,100,'A');
INSERT INTO [GRADE]([low],[up],[rank]) VALUES(80,89,'B');
INSERT INTO [GRADE]([low],[up],[rank]) VALUES(70,79,'C');
INSERT INTO [GRADE]([low],[up],[rank]) VALUES(60,69,'D');
INSERT INTO [GRADE]([low],[up],[rank]) VALUES(0,59,'E');

 

题目：
1、查询Student表中的所有记录的Sname、Ssex和Class列。
2、查询教师所有的单位即不重复的Depart列。
3、查询Student表的所有记录。
4、查询Score表中成绩在60到80之间的所有记录。
5、查询Score表中成绩为85，86或88的记录。
6、查询Student表中“95031”班或性别为“女”的同学记录。
7、以Class降序查询Student表的所有记录。
8、以Cno升序、Degree降序查询Score表的所有记录。
9、查询“95031”班的学生人数。
10、查询Score表中的最高分的学生学号和课程号。
11、查询‘3-105’号课程的平均分。
12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
13、查询所有课程最低分大于70，最高分小于90的Sno列。
14、查询所有学生的Sname、Cno和Degree列。
15、查询所有学生的Sno、Cname和Degree列。
16、查询所有学生的Sname、Cname和Degree列。
17、查询“95033”班所选课程的平均分。
18、查询所有同学的Sno、Cno和rank列。(涉及grade表)
19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
23、查询“张旭“教师任课的学生成绩。
24、查询选修某课程的同学人数多于5人的教师姓名。
25、查询95033班和95031班全体学生的记录。
26、查询存在有85分以上成绩的课程Cno.
27、查询出“计算机系“教师所教课程的成绩表。
28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。
29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
31、查询所有教师和同学的name、sex和birthday.
32、查询所有“女”教师和“女”同学的name、sex和birthday.
33、查询成绩比该课程平均成绩低的同学的成绩表。
34、查询所有目前有带课程的教师的Tname和Depart.
35  查询所有未讲课的教师的Tname和Depart.
36、查询至少有2名男生的班号。
37、查询Student表中不姓“王”的同学记录。
38、查询Student表中每个学生的姓名和年龄。
39、a.查询Student表中最大和最小生日的姓名和生日日期。 b.查询Student表中最大和最小的Sbirthday日期部分。
40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
41、查询“男”教师及其所上的课程。
42、查询最高分同学的Sno、Cno和Degree列。
43、查询和“李军”同性别的所有同学的Sname.
44、查询和“李军”同性别并同班的同学Sname.
45、查询所有选修“计算机导论”课程的“男”同学的成绩表

 

SqlServer写法答案：

--1、 查询Student表中的所有记录的Sname、Ssex和Class列。
select sname,ssex,class from student

--2、 查询教师所有的单位即不重复的Depart列。
select distinct depart from teacher

--3、 查询Student表的所有记录。
select * from student

--4、 查询Score表中成绩在60到80之间的所有记录。
select * from score where degree between 60 and 80

--5、 查询Score表中成绩为85，86或88的记录。

写法一：
select * from score where degree in (85,86,88);
写法二：
select * from score where degree = 85 or degree = 86 or degree = 88

--6、 查询Student表中“95031”班或性别为“女”的同学记录。
select * from student where class=95031 or ssex='女'

--7、 以Class降序查询Student表的所有记录。
select * from student order by class desc

--8、 以Cno升序、Degree降序查询Score表的所有记录。
select * from score order by sno asc,degree desc

--9、 查询“95031”班的学生人数。
select count(*) from student where class = 95031

--10、查询Score表中的最高分的学生学号和课程号。
写法一：
select * from score
where degree = (select max(degree) from score)

写法二：
select top 1 sno,cno from score
order by degree desc;

--11、查询‘3-105’号课程的平均分。
select avg(degree) from score where cno='3-105'

--12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
select cno,AvgScore from 
(select cno,count(cno) as count,avg(degree) as AvgScore from score
group by cno) as A
where a.count>=5 and a.cno like '3%';

--13、查询所有课程最低分大于70，最高分小于90的Sno列。
SELECT SNO FROM SCORE GROUP BY SNO HAVING MIN(DEGREE)>70 AND MAX(DEGREE)<90;

--14、查询所有学生的Sname、Cno和Degree列。
写法一：
select a.sname,b.cno,b.degree from student as a inner join score as b on a.sno = b.sno;
写法二：
select sname,cno,degree from student as a,score as b where a.sno = b.sno;

--15、查询所有学生的Sno、Cname和Degree列。
select a.sno,b.cname,a.degree from score as a inner join course as b on a.cno = b.cno

--16、查询所有学生的Sname、Cname和Degree列。
select c.sname,b.cname,a.degree from score a inner join course b
on a.cno = b.cno
inner join student c
on c.sno = a.sno

--17、查询“95033”班所有课程的平均分。  
SELECT AVG(A.DEGREE) FROM SCORE A JOIN STUDENT B ON A.SNO = B.SNO WHERE B.CLASS='95033';
--各科的平均分：
select cno,avg(degree) from score
where sno in(select sno from student where class=95033)
group by cno

--18、查询所有同学的Sno、Cno和rank列
SELECT A.SNO,A.CNO,B.RANK FROM SCORE A,GRADE B WHERE A.DEGREE BETWEEN B.LOW AND B.UP 
--备注：
select * from score,grade --产生笛卡尔积 记录数=表1记录数*表2记录数

--19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
select * from score 
where cno='3-105'
and degree>(select degree from score where sno=109 and cno='3-105')

--20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
select * from score
where sno in 
(
    select sno from
    (
        select sno,count(cno) as cnt from score 
        group by sno
        ) t
        where t.cnt>1
        and sno not in(select top 1 sno from score order by degree desc
    )
)

--21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
select * from score
where degree > (select degree from score where sno=109 and cno='3-105')

--22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
SELECT SNO,SNAME,SBIRTHDAY FROM STUDENT WHERE YEAR(SBIRTHDAY)=(SELECT YEAR(SBIRTHDAY)
FROM STUDENT WHERE SNO='108');

--23、查询“张旭“教师任课的学生成绩。
select * from score
where cno in
(
select b.cno from teacher a inner join course b on a.tno = b.tno and a.tname='张旭'
)

--类似写法
select sno,cno,degree from score where cno=(select x.cno from course x,teacher y
where x.tno=y.tno and y.tname='张旭');

--24、查询选修某课程的同学人数多于5人的教师姓名。
select tname from teacher
where tno in (
select tno from course
where cno in (select cno from score group by cno having count(cno)>5)
)

--类似写法：
select tname from teacher where tno in(select x.tno from course x,score y where
x.cno=y.cno group by x.tno having count(x.tno)>5);

--25、查询95033班和95031班全体学生的记录。
select * from student where class in(95033,95031);

--26、查询存在有85分以上成绩的课程Cno.
SELECT CNO FROM SCORE GROUP BY CNO HAVING MAX(DEGREE)>85;

--其他方法:
1. select cno from score where degree>85 group by cno;
2.select distinct cno from score where degree in (select degree from score where degree>85);


--27、查询出“计算机系“教师所教课程的成绩表。
select * from score
where cno in(
 select a.cno from course a inner join teacher b on a.tno = b.tno and b.depart='计算机系'
);

--28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。
select tname,prof from teacher
where depart='计算机系'
and prof not in(
  select distinct prof from teacher where depart ='电子工程系'
);

--29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。

SELECT * FROM SCORE WHERE CNO='3-105' AND DEGREE>ANY(SELECT DEGREE FROM SCORE WHERE CNO='3-245') ORDER
BY DEGREE DESC;


--30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
SELECT * FROM SCORE WHERE DEGREE>ALL(SELECT DEGREE FROM SCORE WHERE CNO='3-245') ORDER
BY DEGREE DESC;

--31、查询所有教师和同学的name、sex和birthday.
(select sname as name,ssex as sex,sbirthday as birthday from student) 
union all --union去除重记录 union all不去除
(select tname as name,tsex as sex,tbirthday as birthday from teacher) 


--32、查询所有“女”教师和“女”同学的name、sex和birthday.
(select sname as name,ssex as sex,sbirthday as birthday from student where ssex='女') 
union all 
(select tname as name,tsex as sex,tbirthday as birthday from teacher where tsex='女');

--33、查询成绩比该课程平均成绩低的同学的成绩表。(不太理解)

SELECT A.* FROM SCORE A WHERE DEGREE<(SELECT AVG(DEGREE) FROM SCORE B WHERE A.CNO=B.CNO);

--34、查询所有任课教师的Tname和Depart.
select a.tname,a.depart from teacher a
inner join 
course b 
on a.tno=b.tno;

--其他解法:
解法二：select tname,depart from teacher a where exists
(select * from course b where a.tno=b.tno);
解法三：SELECT TNAME,DEPART FROM TEACHER WHERE TNO IN (SELECT TNO FROM COURSE);

实际分析，第一种揭发貌似更好，至少扫描次数最少。

--35、查询所有未讲课的教师的Tname和Depart.
select tname,depart from teacher
where tno not in(
select tno from course
);

--其他解法：
select tname,depart from teacher a where not exists
(select * from course b where a.tno=b.tno);

--36、查询至少有2名男生的班号。
select class from student
where ssex='男'
group by class
having count(ssex)>1;

--37、查询Student表中不姓“王”的同学记录。
select * from student where sname not like'王%'

--38、查询Student表中每个学生的姓名和年龄。
select sname,(year(getdate())-year(sbirthday)) as age from student;
--类似写法：
select sname,datediff(year,sbirthday,getdate()) as age from student;

--38、查询Student表中每个学生的姓名和年龄。
select sname,(year(getdate())-year(sbirthday)) as age from student;
--类似写法：
select sname,datediff(year,sbirthday,getdate()) as age from student;


--39、a.查询Student表中最大和最小生日的姓名和生日日期
select sname,sbirthday as THEMAX from student where sbirthday =(select min(SBIRTHDAY)
from student)
union
select sname,sbirthday as THEMIN from student where sbirthday =(select max(SBIRTHDAY) from
student);

--b.查询Student表中最大和最小的Sbirthday日期部分。 
select convert(varchar(10),min(sbirthday),120) as [min],convert(varchar(10),max(sbirthday),120) as [max] from student;

--40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
SELECT *,datediff(year,sbirthday,getdate()) AS AGE FROM STUDENT ORDER BY CLASS DESC,AGE DESC;

--41、查询“男”教师及其所上的课程。
select a.tname,b.cname from teacher as a inner join course as b
on a.tno=b.tno where a.tsex='男';

--42、查询最高分同学的Sno、Cno和Degree列。
select * from score
where degree = (
select max(degree) from score
);

--43、查询和“李军”同性别的所有同学的Sname.
select sname from student
where ssex=(
select ssex from student where sname='李军'
);

--44、查询和“李军”同性别并同班的同学Sname.
SELECT SNAME FROM STUDENT A WHERE SSEX=(SELECT SSEX FROM STUDENT B WHERE B.SNAME='李军' )
AND CLASS=(SELECT CLASS FROM STUDENT C WHERE c.SNAME='李军');
--排除“李军”本人：
select sname from student
where ssex=(
select ssex from student where sname='李军'
)
and class = (
select class from student where sname='李军'
)
and sname!='李军';


--45、查询所有选修“计算机导论”课程的“男”同学的成绩表
select * from score where sno in(select sno from student where
ssex='男') and cno=(select cno from course
where cname='计算机导论');

 

MySql写法答案：

1、查询Student表中的所有记录的Sname、Ssex和Class列。
SELECT SNAME,SSEX,CLASS FROM STUDENT;

2、查询教师所有的单位即不重复的Depart列。
SELECT DISTINCT DEPART FROM TEACHER;

3、查询Student表的所有记录。
SELECT * FROM STUDENT;

4、查询Score表中成绩在60到80之间的所有记录。
SELECT * FROM SCORE WHERE DEGREE BETWEEN 60 AND 80;

5、查询Score表中成绩为85，86或88的记录。
SELECT * FROM SCORE WHERE DEGREE IN (85,86,88);

6、查询Student表中“95031”班或性别为“女”的同学记录。
SELECT * FROM STUDENT WHERE CLASS='95031' OR SSEX='女';

7、以Class降序查询Student表的所有记录。
SELECT * FROM STUDENT ORDER BY CLASS DESC;

8、以Cno升序、Degree降序查询Score表的所有记录。
SELECT * FROM SCORE ORDER BY CNO ASC,DEGREE DESC;

9、查询“95031”班的学生人数。
SELECT  COUNT(*) FROM STUDENT WHERE CLASS='95031';

10、查询Score表中的最高分的学生学号和课程号。
SELECT SNO,CNO FROM SCORE WHERE DEGREE=(SELECT MAX(DEGREE) FROM SCORE);
SELECT SNO,CNO FROM SCORE ORDER BY DEGREE DESC LIMIT 1;

11、查询‘3-105’号课程的平均分。
SELECT AVG(DEGREE) FROM SCORE WHERE CNO='3-105';

12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
select avg(degree),cno from score
where cno like '3%'
group by cno
having count(sno)>= 5;

13、查询最低分大于70，最高分小于90的Sno列。
SELECT SNO FROM SCORE GROUP BY SNO HAVING MIN(DEGREE)>70 AND MAX(DEGREE)<90;

14、查询所有学生的Sname、Cno和Degree列。
SELECT A.SNAME,B.CNO,B.DEGREE FROM STUDENT AS A JOIN SCORE AS B ON A.SNO=B.SNO;

15、查询所有学生的Sno、Cname和Degree列。
SELECT A.CNAME, B.SNO,B.DEGREE FROM COURSE AS A JOIN SCORE AS B ON A.CNO=B.CNO ;

16、查询所有学生的Sname、Cname和Degree列。
SELECT A.SNAME,B.CNAME,C.DEGREE FROM STUDENT A JOIN (COURSE B,SCORE C)
ON A.SNO=C.SNO AND B.CNO =C.CNO;

17、查询“95033”班所选课程的平均分。
SELECT AVG(A.DEGREE) FROM SCORE A JOIN STUDENT B ON A.SNO = B.SNO WHERE B.CLASS='95033';

18、查询所有同学的Sno、Cno和rank列。(grade表)
SELECT A.SNO,A.CNO,B.RANK FROM SCORE A,GRADE B 
WHERE A.DEGREE BETWEEN B.LOW AND B.UP
ORDER BY RANK;

19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
SELECT A.* FROM SCORE A JOIN SCORE B 
WHERE A.CNO='3-105' 
AND A.DEGREE>B.DEGREE 
AND B.SNO='109' AND B.CNO='3-105';

另一解法：
SELECT A.* FROM SCORE A  WHERE A.CNO='3-105' 
AND A.DEGREE>ALL(SELECT DEGREE FROM SCORE B WHERE B.SNO='109' AND B.CNO='3-105');

20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
SELECT * FROM score s 
WHERE DEGREE<(SELECT MAX(DEGREE) FROM SCORE) 
GROUP BY SNO 
HAVING COUNT(SNO)>1 ORDER BY DEGREE ;

21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
见19的第二种解法

22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
SELECT SNO,SNAME,SBIRTHDAY FROM STUDENT 
WHERE YEAR(SBIRTHDAY)=(SELECT YEAR(SBIRTHDAY) FROM STUDENT WHERE SNO='108');

ORACLE写法:
select x.cno,x.Sno,x.degree from score x,score y 
where x.degree>y.degree 
and y.sno='109'and y.cno='3-105';

select cno,sno,degree from score 
where degree >(select degree from score where sno='109' and cno='3-105')

23、查询“张旭“教师任课的学生成绩。
SELECT A.SNO,A.DEGREE FROM SCORE A JOIN (TEACHER B,COURSE C)
ON A.CNO=C.CNO AND B.TNO=C.TNO
WHERE B.TNAME='张旭';
另一种解法：
select cno,sno,degree from score 
where cno=(select x.cno from course x,teacher y where x.tno=y.tno and y.tname='张旭');
根据实际EXPLAIN此SELECT语句，第一个的扫描次数要小于第二个

24、查询选修某课程的同学人数多于5人的教师姓名。
SELECT A.TNAME FROM TEACHER A JOIN (COURSE B, SCORE C) ON (A.TNO=B.TNO AND B.CNO=C.CNO)
GROUP BY C.CNO HAVING COUNT(C.CNO)>5;
另一种解法：
select tname from teacher 
where tno in(
select x.tno from course x,score y 
where x.cno=y.cno 
group by x.tno 
having count(x.tno)>5
);
实际测试1明显优于2

25、查询95033班和95031班全体学生的记录。
select * from student where class in(95033,95031);

26、查询存在有85分以上成绩的课程Cno.
SELECT CNO FROM SCORE GROUP BY CNO HAVING MAX(DEGREE)>85;
另一种解法：
select distinct cno from score 
where degree in (select degree from score where degree>85);

27、查询出“计算机系“教师所教课程的成绩表。
SELECT A.* FROM SCORE A JOIN (TEACHER B,COURSE C) ON A.CNO=C.CNO AND B.TNO=C.TNO
WHERE B.DEPART='计算机系';
另一种解法：
SELECT * from score 
where cno in (
select a.cno from course a join teacher b on a.tno=b.tno and b.depart='计算机系'
);
此时2略好于1，在多连接的境况下性能会迅速下降

28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。
select tname,prof from teacher 
where depart='计算机系' 
and prof not in (select prof from teacher where depart='电子工程系');

29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
SELECT * FROM SCORE 
WHERE CNO='3-105' 
AND DEGREE>ANY(SELECT DEGREE FROM SCORE WHERE CNO='3-245') 
ORDER BY DEGREE DESC;

30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
SELECT * FROM SCORE 
WHERE DEGREE>ALL(SELECT DEGREE FROM SCORE WHERE CNO='3-245') 
ORDER BY DEGREE DESC;

31、查询所有教师和同学的name、sex和birthday.
SELECT SNAME AS NAME, SSEX AS SEX, SBIRTHDAY AS BIRTHDAY FROM STUDENT
UNION
SELECT TNAME AS NAME, TSEX AS SEX, TBIRTHDAY AS BIRTHDAY FROM TEACHER;

32、查询所有“女”教师和“女”同学的name、sex和birthday.
SELECT SNAME AS NAME, SSEX AS SEX, SBIRTHDAY AS BIRTHDAY FROM STUDENT WHERE SSEX='女'
UNION
SELECT TNAME AS NAME, TSEX AS SEX, TBIRTHDAY AS BIRTHDAY FROM TEACHER WHERE TSEX='女';

33、查询成绩比该课程平均成绩低的同学的成绩表。(须注意此题)
SELECT A.* FROM SCORE A 
WHERE DEGREE<(SELECT AVG(DEGREE) FROM SCORE B WHERE A.CNO=B.CNO);

34、查询所有目前有带课程的教师的Tname和Depart.
解法一：
SELECT A.TNAME,A.DEPART FROM TEACHER A JOIN COURSE B ON A.TNO=B.TNO;
解法二：
select tname,depart from teacher a 
where exists (select * from course b where a.tno=b.tno);
解法三：
SELECT TNAME,DEPART FROM TEACHER WHERE TNO IN (SELECT TNO FROM COURSE);
实际分析，第一种揭发貌似更好，至少扫描次数最少。

35  查询所有未讲课的教师的Tname和Depart.
解法一：
SELECT TNAME,DEPART FROM TEACHER A LEFT JOIN COURSE B USING(TNO) WHERE ISNUL (B.tno);
解法二：
select tname,depart from teacher a 
where not exists(select * from course b where a.tno=b.tno);
解法三：
SELECT TNAME,DEPART FROM TEACHER 
WHERE TNO NOT IN (SELECT TNO FROM COURSE);
NOT IN的方法效率最差，其余两种差不多

36、查询至少有2名男生的班号。
SELECT CLASS FROM STUDENT A WHERE SSEX='男' 
GROUP BY CLASS HAVING COUNT(SSEX)>1;

37、查询Student表中不姓“王”的同学记录。
SELECT * FROM STUDENT A WHERE SNAME not like '王%';

38、查询Student表中每个学生的姓名和年龄。
SELECT SNAME,(YEAR(NOW())-YEAR(SBIRTHDAY)) AS AGE FROM STUDENT;

39、a.查询Student表中最大和最小生日的姓名和生日日期。 
select sname,sbirthday as THEMAX from student 
where sbirthday =(select min(SBIRTHDAY) from student)
union
select sname,sbirthday as THEMIN from student 
where sbirthday =(select max(SBIRTHDAY) from student);

40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
SELECT CLASS,(YEAR(NOW())-YEAR(SBIRTHDAY)) AS AGE FROM STUDENT 
ORDER BY CLASS DESC,AGE DESC;

41、查询“男”教师及其所上的课程。
SELECT A.TNAME,B.CNAME FROM TEACHER A JOIN COURSE B 
USING(TNO) WHERE A.TSEX='男';

42、查询最高分同学的Sno、Cno和Degree列。
SELECT A.* FROM SCORE A 
WHERE DEGREE=(SELECT MAX(DEGREE) FROM SCORE B );

43、查询和“李军”同性别的所有同学的Sname.
SELECT SNAME FROM STUDENT A 
WHERE SSEX=(SELECT SSEX FROM STUDENT B WHERE B.SNAME='李军');

44、查询和“李军”同性别并同班的同学Sname.
SELECT SNAME FROM STUDENT A 
WHERE SSEX=(SELECT SSEX FROM STUDENT B WHERE B.SNAME='李军' )
AND CLASS=(SELECT CLASS FROM STUDENT C WHERE c.SNAME='李军');

45、查询所有选修“计算机导论”课程的“男”同学的成绩表
解法一：
SELECT A.* FROM SCORE A JOIN (STUDENT B,COURSE C) 
USING(sno,CNO) WHERE B.SSEX='男' AND C.CNAME='计算机导论';
解法二：
select * from score 
where sno in(select sno from student where ssex='男') 
and cno=(select cno from course where cname='计算机导论');

 

文章来源：经典SQL练习题

 

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