、 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>=
60 and degree<=
80
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)
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 Cno ,Degree desc
--
9、 查询“
95031”班的学生人数。 --
聚合函数 针对数据列 计算求和或者计数等一系列算术性问题
--count()，max(),min(),sum(),avg(), count()放的是* 其他的放的是(列名) as起别名 如 count(*)
as 总分
select count(*)
from Student
where Class=
‘95031‘ --
返回结果都是一个数字
--
10、 查询Score表中的最高分的学生学号和课程号。（子查询或者排序）
select *
from Score
where Degree=(
select MAX(degree)
from score)
select top
1 *
from score order by degree desc
--
11、 查询每门课程的平均分。--
当分组和聚合结合的时候 先分组 然后再对每一组分别进行聚合
select AVG(degree)
from score group by cno
--
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,AVG(degree)
from Score
where Cno like
‘3%‘group by Cno having COUNT(*)>
5
--
select cno,AVG(degree)
as degree1
from Score
where Cno like
‘3%‘group by Cno having COUNT(*)>
5 order by degree1 desc
--
13、 查询最低分大于70，最高分小于90的Sno列。
select sno,degree
from Score
where Degree>
70 and Degree <
90
--
14、 查询所有学生的Sname、Cno和Degree列。 --
俩个表一定有主外键关系
--
join前 修饰符 默认inner 最主要的是以重要的表来显示
--
left join左链接以左表为主 左表的信息全部显现出来 右表根据左表的需要显现
--
right join右链接以右表为主 右表的信息全部显现出来 左表根据右表的需要显现
select Sname,Cno,Degree
from Score join student on Score.sno = Student.sno --
on后面跟任意条件 俩表已连接
--
15、 查询所有学生的Sno、Cname和Degree列。
select Sno,Cname,Degree
from Score join course on score.cno=
course.cno
select Sno,(
select cname
from course
where score.cno=course.cno)
as 课程,Degree
from Score --
子查询写法 要求的题目不在同一个表中只能这样写
--
16、 查询所有学生的Sname、Cname和Degree列。
select Sname,Cname,Degree
from student join Score on Student.sno=Score.sno join course on score.cno=
course.cno
--
17、 查询“
95033”班所选课程的平均分。
select AVG(degree)
from Student join score on Student.Sno=Score.Sno
where Class=
‘95033‘
select avg(degree)
from Score t
where sno
in(
select Sno
from Student
where Class=
‘95033‘)
--
18、 假设使用如下命令建立了一个grade表：
create table grade(low int,upp
int,rank
char(
1))
insert into grade values(90,
100,
‘A‘)
insert into grade values(80,
89,
‘B‘)
insert into grade values(70,
79,
‘C‘)
insert into grade values(60,
69,
‘D‘)
insert into grade values(0,
59,
‘E‘)
--
现查询所有同学的Sno、Cno和rank列。
select Sno,Cno,rank
from Score,grade
where Degree between low and upp order by rank --
select连接查询 where后面跟的是条件
select Sno,Cno,rank
from Score join grade on degree between low and upp order by rank --
join on连接查询 on后面跟的是条件
select sno,cno,(
select RANK
from grade
where Score.Degree between low and upp )
as 级别
from score order by Degree desc --
子查询写法 要求的题目不在同一个表中只能这样写
--
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中选学多门课程的同学中分数为非最高分成绩的记录。3种歧义
--
1.查询学号出现俩次以上的学号来
select sno
from Score group by Sno having count(*)>
1
--
2.查询步骤一中的学号的人的分数
select*
from Score
where Sno
in(
select sno
from Score group by Sno having count(*)>
1)
--
3.查询所有人的分数最高分来
select max(degree)
from Score
--
4.从步骤2中剔除最高分的加上步骤3
select*
from Score
where Sno
in(
select sno
from Score group by Sno having count(*)>
1)and Degree<(
select max(degree)
from Score )
--
去掉选多门课程并且每一门最高分成绩的记录。
select *
from score
as a
where degree <(
select MAX(degree)
from score
as b
where a.cno = b.cno)and sno
in(
select sno
from score group by sno having COUNT(*)>
1 )
--
去掉选多门课程所有门中的最高分成绩的记录。
select *
from score
where Degree < (
select MAX(Degree)
from Score
where sno
in(
select sno
from score group by sno having COUNT(*)>
1 )) and sno
in(
select sno
from score group by sno having COUNT(*)>
1 )--
后面的sno选出课程大于1的课程
--
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 degree
from score join course on Score.Cno=course.cno join teacher on course.tno=teacher.tno
where Tname=
‘张旭‘
select degree
from score
where cno
in(
select cno
from course
where tno
in (
select tno
from Teacher
where 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(*)>
5))
--
25、查询95033班和95031班全体学生的记录。
select Student.Sno, Student.Sname, Student.Ssex, Student.Sbirthday, Student.Class,Score.Cno,Score.Degree
from Student join Score on Student.Sno=
Score.Sno
--
26、 查询存在有85分以上成绩的课程Cno.
select distinct cno
from Score
where deGree>=
85
--
27、查询出“计算机系“教师所教课程的成绩表。
select sno,course.Cno,degree
from Score join course on Score.Cno=course .Cno join Teacher on course .tno = Teacher.Tno
where Depart=
‘计算机系‘
select sno,Cno,degree
from Score
where cno
in(
select Cno
from course
where Tno
in(
select Tno
from Teacher
where Depart=
‘计算机系‘) )
--
1、嵌套查询中的IN, 集合中可能有多个也可能只有一个值
--
2、任何一个子查询都是select块，一定要加上（），否则就会报错.
--
3、任何一个子查询都不能用order by来排序，只能对最终的查询结果进行排序
--
4、子查询的结果只是作为父查询的某一个条件而已，还可以用AND,OR等追加更多的条件
--
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 Prof not
in(
select Prof
from Teacher
where Depart =
‘电子工程系‘ and Prof
in (
select Prof
from Teacher
where Depart =
‘计算机系‘))
and Depart in(
‘计算机系‘,
‘电子工程系‘) --
此语句无法转换为一个联接。
--
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 cno,Sno,degree
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 cno,Sno,degree
from score
where Cno=
‘3-105‘and Degree>all(
select max(Degree)
from Score
where Cno=
‘3-245‘)
--
31、 查询所有教师和同学的name、sex和birthday. --
用union注意 列相等 数据类型一样
select sname,ssex,Sbirthday
from Student
union
select tname,ssex,sbirthday
from teacher
--
32、查询所有“女”教师和“女”同学的name、sex和birthday.
select sname,ssex,Sbirthday
from Student
where Ssex=
‘女‘
union
select tname,ssex,sbirthday
from teacher
where Ssex=
‘女‘
--
33、 查询成绩比该课程平均成绩低的同学的成绩表。
select *
from score
as a
where degree<(
select AVG(degree)
from score
as b
where b.cno = a.cno ) --
相关子查询
select *
from score
as a
where 64<(
select AVG(degree)
from score
as b
where b.cno =
‘3-105‘) --括号里面相当于求的是
‘3-105‘的平均分 没必要再分组
--
34、 查询所有任课教师的Tname和Depart
select Tname,Depart
from Teacher
where Tno
in (
select distinct tno
from course)
--
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 distinct tno
from course)
--
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 (*)>=
2
--
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 年龄
from student
--
39、查询Student表中最大和最小的Sbirthday日期值。
select MAX(Sbirthday)
as 最大,MIN (Sbirthday)
as 最小
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 *
from Student order by
class desc,
--
41、查询“男”教师及其所上的课程。
select *
from Teacher join Course on Teacher.Tno=Course.Tno
where ssex=
‘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)
select top
1 *
from Score order by Degree desc
--
43、查询和“李军”同性别的所有同学的Sname.
select Sname,SSEX
from Student
where Ssex
in(
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
where Ssex
in(
select Ssex
from Student
where Sname=
‘李军‘) and Class
in(
select Class
from Student
where 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
in(
select Cno
from Course
where Cname=
‘计算机导论‘
数据库习题
标签：
