【SQL server基础】初步学习存储过程（好学易懂）

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-------------------------------存储过程Study------------------------------
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--删除表
drop table student
go  

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--创建用户信息数据表
create table student
(
    id int identity(,),--递增1,
    stuNo varchar() primary key, --唯一键
    stuName varchar(),
    stuAge datetime,
    stuSex varchar()
)  

--创建用户分数数据表
create table course
(
    id int identity(,),--递增1,
    stuNo varchar(),
    courseName varchar(),
    courseScore decimal
)  

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--插入数据
--插入单条数据
insert into student(stuNo,stuName,stuAge,stuSex) values('','王男','1996-08-27 09:00:00.000','男')  

--多数量插入数据
--SQL Server2008特有的插入
insert into student values('','杨幂','1995-4-20 6:0:0','女'),
                          ('','程峰','1988-9-17 15:30:0','男')  

insert into course values('','思想政治','85.5'),
                         ('','数学',''),
                         ('','语文',''),
                         ('','物理',''),
                         ('','化学',''),
                         ('','英语','')  

insert into course values('','思想政治',''),
                         ('','数学',''),
                         ('','语文',''),
                         ('','物理',''),
                         ('','化学',''),
                         ('','英语','')                          

--使用UNION ALL来进行插入
insert into student
select '','wangan','1895-5-27 14:30:28','女'
union all
select '','zhangnan','1990-1-20 19:0:0','女'
go  

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--修改数据
update student set stuSex='男',stuAge='2016-5-9 8:0:0' where stuName='王男'
go  

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--删除数据
delete from student where stuNo=
go  

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--存储过程查询所有数据
--begin...end 类似编程语言中的{}
create proc stu1
as
begin
    select * from student;
end
go  

exec stu1
go  

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--存储过程根据条件用户名查询用户信息
create proc stu2
@sname varchar()   --声明全局变量
as
begin
    select * from student s where s.stuName=@sname;
end
go  

exec stu2 '王男'
go  

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--存储过程内部设定用户名查询用户信息
create proc stu3
@sname varchar()='王男'
as
begin
    select * from student s where s.stuName=@sname;
end
go  

exec stu3
go  

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--存储过程根据用户名查询是否存在这个用户信息
create proc stu4
@sname varchar(),
@result varchar() output --输出参数
as
begin
     if (select COUNT() from student s where s.stuName=@sname)>
     --if exists (select COUNT() from student s where s.stuName=@sname)
     set
        @result='存在!'
     else
     set
        @result='不存在!'
end
go  

declare @result varchar()
exec stu4 '王男1',@result output
print @result
go  

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--存储过程内部设定局部变量用户名来查询用户信息
create proc stu5
as
declare @sname varchar()  --局部变量声明
set @sname='杨幂'
begin
    select * from student s where s.stuName=@sname
end
go  

exec stu5
go  

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--存储过程根据条件用户学号查询用户名
create proc stu6
@stuNo varchar()
as
declare @sname varchar()
set @sname=(select s.stuName from student s where s.stuNo=@stuNo)
select @sname
go  

exec stu6 ''
go  

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--存储过程插入用户信息
create proc stu7
@stuNo varchar(),
@stuName varchar(),
@stuAge datetime,
@stuSex varchar()
as
begin
    insert into student
        (stuNo,stuName,stuAge,stuSex)
    values
        (@stuNo,@stuName,@stuAge,@stuSex)
end
go  

exec stu7 '','王莽','2000-9-9 9:9:9','女'
go  

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--存储过程根据用户名来删除对应的用户信息
--@@rowcount返回操作条数
--return返回信息，终止下面的操作
create proc stu8
@stuName varchar()
as
begin
    delete from student where stuName=@stuName
    return @@rowcount
end
go  

declare @result varchar()
exec @result=stu8 '王莽'
select @result as '删除条数'
--print @result
go  

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--存储过程根据用户学号来查询他的平均分
create proc stu9
@stuNo varchar(),
@avg int output
as
begin
    set @avg=(select AVG(courseScore) from course where stuNo=@stuNo)
    --等同
    --select @avg=AVG(courseScore) from course where stuNo=@stuNo
end
go  

declare @avg int
exec stu9 '',@avg output
print @avg
go  

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--存储过程根据用户学号来联合查询用户信息和课程信息
create proc stu10
@stuNo varchar()
as
    select c.stuNo,s.stuName,s.stuAge,s.stuSex,c.courseName,c.courseScore from student s join course c on s.stuNo=c.stuNo where s.stuNo=@stuNo
go  

exec stu10 ''
go  

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--存储过程判断学号是否存在，不存在，插入用户信息，返回消息；存在，返回信息
create proc stu11
@stuNo varchar(),
@stuName varchar(),
@stuAge datetime,
@stuSex varchar(),
@result varchar() output
as
    if exists (select * from student where stuNo=@stuNo)
        begin
            set @result='对不起，学号已存在!'
        end
    else
        begin
            insert into student
                (stuNo,stuName,stuAge,stuSex)
            values
                (@stuNo,@stuName,@stuAge,@stuSex)
            set @result='恭喜你，用户信息插入成功!'
        end
go  

declare @result varchar()
exec stu11 '','王忠磊','1980-8-8 8:9:0','男',@result output
print @result  

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--存储过程查询当前用户的平均成绩与总的平均成绩之间的关系
create proc stu12
@stuNo varchar()
as
declare @curAvg decimal(,)
declare @totalAvg decimal(,)
if exists(select * from course where stuNo=@stuNo)
    begin
        set @totalAvg=(select AVG(courseScore) from course)
        select @curAvg=AVG(courseScore) from course where stuNo=@stuNo
        print ('总的平均分:'+convert(varchar(),@totalAvg))
        print ('该生的平均分:'+convert(varchar(),@curAvg))
        if @curAvg>@totalAvg
            print '高于平均水平!'
        else
            print '低于平均水平!'
    end
else
    print '该生对应的分数信息不存在,请重新查询!'
go  

exec stu12 ''
go