SQL语句练习二

use LIANXI
Create table student--学生表
(
ssno    varchar(50) not null primary key,--主键学生学号
ssname varchar(50) not null,--学生姓名
sssex  varchar(50) not null,--学生性别
sbirthday date,--学生出生年月
ssclass varchar(50) not null,--学生班级
)
--primary key identity(1,1)自增长加入后设置的列无需输入也可自动成序号并排序，此列若需手动输入，就不
insert into student values('108','曾华','男','1977-09-01','95033')
insert into student values('105','匡明','男','1975-10-02','95031')
insert into student values('107','王丽','女','1976-01-23','95033')--学生信息
insert into student values('101','李军','男','1977-02-20','95033')
insert into student values('109','王芳','女','1975-02-10','95031')
insert into student values('103','陆君','男','1974-06-03','95031')

create table teacher--教师表
(能用自增长
jsno varchar(50) not null primary key,--主键 教师工号
jsname varchar(50) not null ,--教师名字
jssex varchar(50) not null,--教师性别
tbirthday    date,--教师出生年月
jsprof varchar(50) not null,--教师职称
jsdepart varchar(50) not null,--教师所在部门
)
insert into teacher values('804','李诚','男','1958-12-02','副教授','计算机系')
insert into teacher values('856','张旭','男','1969-03-12','讲师','电子工程系')
insert into teacher values('825','王萍','女','1972-05-05','助教','计算机系')--教师信息
insert into teacher values('831','刘冰','女','1977-08-14','助教','电子工程系')
  
create table course --课程表
(
kcno varchar(50) not null primary key,--课程号 主键
kcname varchar(50) not null,--课程名称
jsno varchar(50) references teacher(jsno) not null,--教师工号
)
insert into course values('3-105','计算机导论','825')
insert into course values('3-245','操作系统','804')
insert into course values('6-166','数字电路','856')--输入课程
insert into course values('9-888','高等数学','831')

create table score --成绩表
(
ssno varchar(50) references student(ssno) not null,--学生学号外键
kcno varchar(50) references course(kcno) not null,--课程外键
degree int not null,--课程成绩
)
insert into score values('103','3-245',86)
insert into score values('105','3-245',75)
insert into score values('109','3-245',68)--输入成绩
insert into score values('103','3-105',92)
insert into score values('105','3-105',88)
insert into score values('109','3-105',76)
insert into score values('101','3-105',64)
insert into score values('107','3-105',91)
insert into score values('108','3-105',78)
insert into score values('101','6-166',85)
insert into score values('107','6-166',79)
insert into score values('108','6-166',81)


--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 ssno,ssname,sbirthday from student where YEAR(sbirthday)=(select YEAR(sbirthday)from student where ssno='108')
 --YEAR(sbirthday)提取年
 --month()提取月
 --day()提取天
 --dayofyear 
 print datediff(day,'1994-3-12','2015-4-23')--计算两个日期之间的天数 datediff，datepart返回一个int数值
 print datename(weekday,'2015-4-23')--计算今天值周几，datename返回一个字符串 
 print getdate()--获取当前系统时间
 --23、查询“张旭“教师任课的学生成绩
select *from score where kcno in
(select kcno from course where jsno in (select jsno from teacher where jsname='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 jsname from teacher where jsno in 
(select jsno from course where kcno in 
(select kcno from score group by kcno having COUNT(*)>5))
--25、查询95033班和95031班全体学生的记录。
 select *from student where ssclass in('95033','95031')
26、  查询存在有85分以上成绩的课程Cno.
select kcno 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
select * from teacher
select * from course
select * from score where kcno in(
select kcno from course where jsno in(
select jsno from teacher where jsdepart='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 jsname,jsprof from teacher where jsprof not in
(select jsprof from teacher group by jsprof having  count(*)>1)
select jsname,jsprof from teacher where jsprof not in 
(select jsprof from teacher group by jsprof having  count(*)>1)

select jsname,jsprof  from teacher where jsprof  not in(select jsprof  from teacher where jsprof  in (select jsprof from teacher where jsdepart='计算机系') and jsdepart='电子工程系')and jsdepart  in('计算机系','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 kcno='3-105' and degree>(select min (degree) from score where kcno='3-245')
order by degree desc
select * from score where kcno='3-105' and degree>any(select degree from score where kcno='3-245')
--any前面必须跟比较值 any比较任何一个数 也就是3-245中所有的数 包括最小的数
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 kcno='3-105' and degree>(select max(degree) from score where kcno='3-245')
 31、 查询所有教师和同学的name、sex和birthday.
select ssname,sssex,sbirthday from student 
union
select jsname,jssex,tbirthday from teacher
32、查询所有“女”教师和“女”同学的name、sex和birthday.
select ssname,sssex,sbirthday from student where sssex='女'
union
select jsname,jssex,tbirthday from teacher where jssex='女'
--union 纵向连接 与 join on 横向连接 不同 两个标的数据类型必须一致不然连不到一起去
--列数也要对应 
33、 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 a.kcno=b.kcno)
34、 查询所有任课教师的Tname和Depart.
select * from course
select *from score 
select *from teacher 
select jsname,jsdepart from teacher where jsno in(select jsno from course where kcno in(select kcno from score))
35 、 查询所有未讲课的教师的Tname和Depart. 
select jsname,jsdepart from teacher where jsno not in(select jsno from course where kcno in(select kcno from score))

36、查询至少有2名男生的班号。
select *from student
select ssclass from student where sssex='男'  group by ssclass having COUNT(*)>=2

37、查询Student表中不姓“王”的同学记录。
select *from student where ssname not like '王%'
38、查询Student表中每个学生的姓名和年龄。
select ssname,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),MIN(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 *from student order by ssclass desc,sbirthday asc

 --41查询“男”教师及其所上的课程
select kcname from course where jsno in(select jsno from teacher where jssex='男')

 42、查询最高分同学的Sno、Cno和Degree列。
 select ssno,kcno,DEGREE from score where degree IN(select max(degree) from score)
 
43、查询和“李军”同性别的所有同学的Sname.
select ssname from student where sssex in(select sssex from student where ssname='李军')

44、查询和“李军”同性别并同班的同学Sname.
select ssname from student where sssex in(select sssex from student where ssname='李军')
and ssclass in (select ssclass from student where ssname='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 ssno in (select ssno from student where sssex='男') and
kcno in (select kcno from course where kcname='计算机导论')


select LEFT('abcdef',2)--从左到右截取固定长度
select RIGHT('abcdef',2)--从右往左截取固定长度
select LOWER('ABC')--转换为小写
select UPPER('abc')--转换为大写
select LEN('qweqwe')--返回一个字符串 长度（int值）
print LTRIM('                          adasj dajk                       ')--LTRIM去除字符串左边的空格
print RTRIM('                          adasj dajk                       ')--RTRIM去除字符串右边的空格
print substring('daskdjaskdjwioado',6,2)--从起始位置开始截取固定长度 从6 开始 6为1 所以第二个数是 a
print replace('ssdadasrwfa','ss','jk')--第一个是字符串 第二个是被替换的目标 第三个是要替换成的字符串
print replicate('sd',10)--复制 把 sd 复制10遍
print str(123.456,2,2)




--存储过程
--定义变量
declare @bianliang int
set @bianliang=12--变量赋值
select @bianliang--结果框查看
print @bianliang--消息框查看
-----------------定义两个变量求和
declare @bianliang1 int,@bianliang2 int
set @bianliang1=1
set @bianliang2=2
select @bianliang1+@bianliang2
---创建存储过程
create proc  chaxun
as--as...go中间写存储过程
   select *from student
go
--存储过程创建后，会存储到对应数据库的可编程性》存储过程文件夹下
exec chaxun--执行存储过程

--带返回值的存储过程

create proc returncount
as
   declare @a int
   select @a=COUNT(*) from student--查询结果赋值给了变量@a
   return @a--存储过程返回值
go

declare @jieshou int--定义一个变量接受存储过程返回值
exec @jieshou=returncount--正在执行存储过程时，用接受变量去接受返回值
print @jieshou--输出接受结果

-----------带输入参数的存储过程
create proc Jiafa
@a int,--输入参数，（用逗号隔开，放在as和存储过程名之间）
@b int--输入参数
as
   return @a+@b
go
declare @a int
exec @a=Jiafa 1,7 --调用带参数的存储过程，需要在存储过程名后输入参数，空格隔开，参数之间“，”隔开
print @a

------输入一个0--100之间的数，判断是一位数还是两位数，返回数字1，2 不在范围内返回 -1
create proc pandingshuzi--创建存储过程
@a int--存储过程的输入参数
as
   if @a>0 and @a<10
   begin
      return 1
   end
   else if @a>=10 and @a<100
   begin
      return 2
   end
   else 
   begin
      return -1
   end
go
declare @a2 int--在过程外定义一个接受变量a 用来接受 存储过程
exec @a2=pandingshuzi 999--@a2
print @a