SqlServer基础语句练习（一）

      学了不少东西，感觉自己的sql语句还是很不好，从基础学起吧。

    来一段sql脚本：

create database tongji
go
use tongji
go
create table student
(
Sno varchar(20) not null primary key ,--学号
Sname varchar(20) not null,--学生姓名
Ssex varchar(20) not null, --学生性别
Sbirthday datetime,--学生出生年月
Class varchar(20)--学生所在班级
)
go
create table teacher--老师
(
Tno varchar(20) not null primary key ,--教工编号（主码）
Tname varchar(20) not null,--教工姓名
Tsex varchar(20) not null, --教工性别
Tbirthday datetime,--教工出生年月
Prof varchar(20),--职称
Depart varchar(20) not null--教工所在部门
)
go
create table Course--课程
(
Cno varchar(20) not null primary key ,--课程号
Cname varchar(20) not null,--课程名称
Tno varchar(20) not null references teacher(Tno), --教工编号（外码）
)
go
create table Score--分数
(

Sno varchar(20) not null references student(Sno), --学号（外码）
Cno varchar(20) not null references Course(Cno), --课程号（外码）
primary key(Sno,Cno),
Degree Decimal(4,1),--成绩

)

开始写练习sql语句：

-- 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

--4.查询Score表中成绩为85，86或88的记录。
select * from Score where degree in(85,86,88)

--5.查询Student表中“95031”班或性别为“女”的同学记录。
select * from student where [class]	='95031' and Ssex='女'
--6.以Class降序查询Student表的所有记录。
select * from student order by class desc
--7.以Cno升序、Degree降序查询Score表的所有记录。
select * from Score order by cno,degree desc

--8.查询“95031”班的学生人数。
select COUNT(*) from student where Class='95031'

--9. 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 Sno,Cno from Score where degree=(select MAX(degree) from score)

--10.查询每门课的平均成绩。
select cno,AVG(degree) from Score group by Cno

--11.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) from Score where cno like'3%' group by Cno having  COUNT(*)>=5
select Avg(degree) from Score group by Cno having COUNT(*)>=5 and Cno like'3%'

--12.查询分数大于70，小于90的Sno列。
select sno from Score where degree>70 and DEGREE<90

--13.查询所有学生的Sname、Cno和Degree列。
select sname,cno,degree from score join student on score.sno = student.sno

--14.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

--15.查询所有学生的Sname、Cname和Degree列。
select sname,cname,degree from score join student on student.sno=score.sno join course on score.cno = course.cno
select sname,cname,degree from score,student,course where student.sno=score.sno and score.cno = course.cno

--16查询“95033”班学生的平均分。
select AVG(degree) from Score where Sno in(select Sno from student where Class='95033')

-- 17.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 Sno='3-105')
select * from Score where Cno='3-105' and DEGREE>(select MAX(DEGREE) from Score where Sno='109')

 
 --18.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。
 select * from Score a where Sno in (select Sno from Score group by Sno having COUNT(*)>1) and DEGREE <(select MAX(DEGREE) from Score b where b.Cno=a.Cno)

  --19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 Sno='3-105')


 --20 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 * from student where YEAR(Sbirthday) =(select YEAR(Sbirthday) from student where Sno='108')

--21. 查询“张旭“教师任课的学生成绩。
  select * from Score where cno in (select cno from Course where Tno in(select Tno from teacher where Tname='张旭'))

--22.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))

--23.查询95033班和95031班全体学生的记录。
  select * from student where Class in(95033,95031)

--24.查询存在有85分以上成绩的课程Cno.
select distinct cno from score where degree>85

-25查询出“计算机系“教师所教课程的成绩表。
select * from Score where Cno in(select Cno from Course where Tno in(select Tno from teacher where Depart='计算机系'))

--26.--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')union
select  tname,prof from teacher where Depart='电子工程系' and Prof not in(select Prof from teacher where Depart='计算机系')

select tname,Prof from teacher a where Prof not in(select Prof from teacher b where b.Depart!=a.Depart)

--27.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。
--sqlserver 中 修改比较运算符：All 、Any、Some  其中Some 和Any 等价  作用于比较运算符和子查询之间 (https://technet.microsoft.com/zh-cn/library/ms187074(SQL.90).aspx)
select * from Score where Cno='3-105' and DEGREE>any(select DEGREE from Score where Cno='3-245')

----28、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 cno='3-105' and degree>any(select degree from score where cno='3-245')

--29、 查询所有教师和同学的name、sex和birthday.

select sname,ssex,sbirthday from student
union
select tname,tsex,tbirthday from teacher

--30、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,tsex,tbirthday from teacher where tsex='女'

--31、 查询成绩比该课程平均成绩低的同学的成绩表。

select * from score a where degree<(select avg(degree) from score b where b.cno=a.cno)

--32、 查询所有任课教师的Tname和Depart.

select tname,depart from teacher where tno in(select tno from course where cno in (select distinct cno from score))

--33 、 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 where cno in (select distinct cno from score))

--34、查询至少有2名男生的班号。

select class from student where ssex='男' group by class having count(*) >1

--35、查询Student表中不姓“王”的同学记录。

select * from student where sname not like '王%'

--36、查询Student表中每个学生的姓名和年龄。 YEAR(GETDATE())-YEAR(Sbirthday) 表示你的年龄

select sname,YEAR(getdate())-YEAR(sbirthday) from student

--37、查询Student表中最大和最小的Sbirthday日期值。

select max(sbirthday),min(sbirthday) from student

--38、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,sbirthday asc

--39、查询“男”教师及其所上的课程。

elect cname from course where tno in(select tno from teacher where tsex='男')

select tname,cname from course,teacher where course.tno = teacher.tno and teacher.tsex='男'

--40、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

--41、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')

--42、查询和“李军”同性别并同班的同学Sname.

select sname from student where ssex=(select ssex from student where sname='李军') and class = (select class from student where sname='李军')

--43、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')